"the existence of 2 or even 3 popes, as well as the exclusion of the Bishop of Rome from his own diocese for many decades points to total apostasy by any reasonable standard."

I disagree that a string of bad popes or the expulsion of a pope from Rome constitutes universal apostasy within the Universal Church. If you want to find apostasy, or at the very least, heresy and schism of the type warned about by John in his letters, look no further to the "Reformationists" (Luther and Zwingli and Calvin, all of whom couldn't even agree on the basics of "mere Christianity," the liturgy, and core theology) who didn't really "reform" anything but only lead the universal into not being so universal anymore. If you want to see the actual fruit of the Reformation, which the Church acknowledges was important to combat corruption and abuses within the Church, look no further than the Council of Trent in 1545, where the same systematic problems proclaimed by the Reformers were addressed.

You bring up the East-West schism in Catholicism as a note against its unity, but most of the East-West differences are liturgical or center on canon law, which is called lower-case-t "tradition" and therefore not infallible. So the Eastern Church baptizes and confirms infants at the same time and the Latin Church typically spaces the two out... things like that are more a matter of preference, history, culture, and tradition. What we have within Protestant circles, if you were going to subject them to the same standard of analysis, is complete disarray, with somewhere north of 14,000 "denominations" all with some claim on legitimacy and divine authority just because a few people can get together around a Bible and claim they understand it... with many denominations in heated debate with one another over core doctrinal matters like whether or not God really is "Triune" or whether Jesus really was divine...etc. What do you have but confusion and absurdity to guide oneself in such a landscape? How does a text like the Bible, claiming to be the word of God, suddenly produce thousands upon thousands of different and conflicting opinions? Thus is Protestantism.

What is clear is that when Christ was on Earth performing his earthly ministry, He established "a Church." He did not establish a "denomination." And when asked about how we should deal with a dispute, he told us, "take it to the Church" (Matthew 18:17). What "Church" was He talking about? The Methodist Church? The Lutheran Church? The Southern Baptist Church? If I want to be a good Christian and follow the instruction of Christ in this matter, what ONE single "Church" is he talking about other than the one He was building, founded on the Apostles, founded on Peter the Rock... the "one" Church. And thus Christ didn't want there to be 14,000 different churches, but that "they may all be one..." (John 17:21).

Peter's ministry ended in Rome, and that's where the Church went, because once again, Christ made him the "Rock of the Church." His ministry didn't end in the East. The only reason why the East makes the claims that it does is because during the reign of Justinian and during the split of the Roman Empire, the center of power shifted from Rome to Byzantium. Christ never specified that the "Rock" of the Church must be based wherever the current center of world power rests... but wherever Peter the Apostle rests, whether it is the power center of the world or not. Right now, no one would argue that neither Rome Italy or Istanbul Turkey are the "centers" of world power. The difference is that Peter the Apostle was in Rome, regardless of the city's status, and so that is where the Church was rooted.

The denominations all largely disagree with one another on core theological matters. These things are important and do make it kind of a big deal when deciding which denomination to choose, otherwise people might as well join the "LDS Church" or the Jehova's Witnesses. They're all "anti-Catholic" too. I can't tell you how many people I've seen turned off of Christianity completely because they can't tell which "church" to go to, and all they see is how they're all fighting with one another. Martin Luther may be proud of that legacy, but the Universal Church sees it as a very unfortunate source of scandal that has harmed Christian unity for the last 500 years.

I'm curious about why you can not accept the doctrine that the Blessed Virgin was assumed, and yet accept fully the doctrine regarding the Trinity? If I was going to use those same words that you quote from that document and use them in regards to the doctrine on the canon of scripture, and say "Hence if anyone, which God forbid, should dare willfully to deny or to call into doubt that which we have defined [about the canon of scripture], let him know that he has fallen away completely from the faith...etc" you would probably agree. You would probably agree that we shouldn't just, on a whim, decide to start ousting books from the Bible just because we don't like them, or start writing up some new ones...etc. You'd probably say that doing such would constitute that someone has indeed "fallen away" from the faith. Why? Because they'd be running contrary to what has been "infallibly defined" as scripture or as "capital-T-Tradition." The belief in the assumption of the Blessed Virgin has been attested to and believed for hundreds of years, and it also makes theological sense given the uniqueness of the Blessed Virgin in God's creation. I think you need to define what your general problem is with the Blessed Mother.

As far as numbers go, the Catholic Church is by far the largest segment of Christians in the world compared to all those upwards of 14,000 denominations of protestants. The last I heard there was about 1.2 billion Catholics on the earth. What single denomination of protestants can top that?

I think we can both agree that Protestantism and Catholicism both have blood on their hands. I point out the Puritan settlements that resorted to anti-witchcraft paranoia were Calvinist Presbyters. But even besides all that, I've done my fair share of reading on the history of the Unitarian church from the writings of the Transcendentalists, and from what I can gather, Calvin split from Catholicism, Presbyterianism split from Calvinism, Unitarianism split from Presbyterianism, Unitarian-Universalism split from Unitarianism, and Transcendentalism then split from Unitarian-Universalism, and from there it was only a few skips away from "nature spirits" and soft atheism. Thus is Protestantism. It is confusing and theologically hazardous. I don't like confusion so I became Catholic.

You are absolutely right about Christ being worshiped in the moment rather than in some particular moment in the past. What you describe in that sense is exactly the spirit that fueled Vatican II, and exactly why the Church undertook that council, and why Latin is now "optional." It's not ruled out like it is in most Protestant denominations, but it's also not mandatory as it once was. Why must everything be "one way or the other?"

I understand the topic is "Why aren't you Catholic" ... but I pose this counter-topic to you and ask "Why should I be Protestant?" What am I "protesting?" and why should I be? What church is the true church? Shouldn't that be easy to know? The early disciples certainly thought so, which is why they distinguished it by four marks: the Church is "one, holy, universal ("catholic"), and apostolic." In what Protestant church do all four of those marks apply?