Well, it's one of many nutty symptoms. Honestly, what one does in the privacy of one's bedroom is nobody's business but their own (unless, of course, one is hurting one's self or others)
I completely agree with your second sentence. You first sentence, shows the slippery logic being applied here. The OP starts out saying fundamentalists are all bat-sh** crazy. I agree that many of them probably are and that fundamentalism is a problem here and around the world. However, not all fundamentalist Christians are mean and insane, and it is slander to say so.
However, now the goal post continues to move, and it's not just the angry, fearful, conspiracy theorists that self-select their presence on boards where their warped views are accepted and encouraged. Now all conservative Christians are being lumped in and being called nuts because they share some views with the bat-sh** crazy people.
And, then we see basically all Christians of any viewpoint lumped in because they are somehow not vocal enough in their rejection of fundamentalism, even though they are and this has been pointed out throughout the thread.
Examples are provided and those examples are not sufficient. You fight against creationism in the schools, that's not enough. You fight against the nuts burning the Koran, not enough. Post you disagreement on discussion boards like this, not enough. Write a book that points out the evils of fundamentalism? Not enough. The goal post moves.
The next move in the game, now that all Christians have been lumped together as somehow supporting extremism in one way or another, is to describe how the fundamentalists are the true Christians, the ones you can respect for their 'honesty,' and those who speak against fundamentalism are not really good Christians, but wishy-washy, pick and choose Christians.