Given that there are desires that are not towards sinful activities (e.g. I desire to serve God - at least on a good day), it's possible to argue that the term 'sinful desires' can be parsed in the way you want it to. :)

On the other hand we do need to jump on the propensity to regard ourselves as so much worse than other Christians whose sins are more socially acceptable. One of the biggest problems with churches is the degree to which we are all there presenting our smiley face that suggests we never sin, making anyone who wanders in knowing they are a sinners feel rejected and generating the complaint 'Christians are hypocrites'. It is one of the strengths of the traditional liturgy of the Anglican Book of Common Prayer that it started EVERY service with a call to personal confession of our sins; sadly more modern liturgies have lost that element, which has long since faded from less liturgical churches, with the result that we are often not encouraged to face up to our true nature on a regular basis (yes - I know a formal liturgy doesn't necessarily engage our attention when we hear it...). Of course the Catholic tradition of confession to a priest that was largely rejected in Protestant circles, due to abuses that had come in, at the time of the Reformation is even more effective - again at least on a good day.

You can spot the bad church when the only sins they talk about are the ones that noone in the congregation is likely to be committing; sadly this is one of the reasons that the gay issue that such an airing in certain circles - it's often used as an opportunity for the bad preacher to make his hearers feel good about themselves by denigrating 'those awful gays doing unnatural acts, muggers beating up old ladies, ... politicians supporting ..., [insert your favourite scapegoat here] yadda yadda yadda'. NOT healthy.

An interesting biblical example of how to get at your listeners is provided in the first 2 chapters of Amos; after briefly condemning all the surrounding nations for their sins, including the southern kingdom of Judah, he finally lays into his hearers in the northern kingdom of Israel and shows they are at least as bad... worth looking at as a pattern for a sermon where you want to challenge your listeners, though don't expect to get invited back if you do take that approach!