I'm asking for an example of Christians taking action to prevent their religious message from being misconstrued by the 'nutjobs'.
It is pretty easy to just say a Christian isn't responsible for people who misconstrue their religious message. But Christians should recognize they are responsible if they have done nothing to prevent such 'nutjobs' from acting other than to say, "not my problem, I don't agree. That's all I am responsible for, saying I don't agree."
Christians are indeed responsible for at least making an effort to stop the nutjobs from misinterpreting the religious tenets. I don't hold Christians responsible for succeeding, but I do hold them all responsible for more than just saying they don't agree. Sorry, but that is my view.
He was IN CHURCH. With OTHER CHRISTIANS. He himself was a Christian...and quite OBVIOUSLY made a more than heroic effort to not let Christian teachings be misrepresented. As did those who shared fellowship with him, knowing that he had been more than simply threatened.
MANY churches/denominations make huge efforts to embrace things that extremist nutjobs act stupid about. Check out the churches that perform gay marriage ceremonies even when the states won't recognize them. Check out churches that welcome divorced people. Check out churches that open their arms to anyone and everyone the extremists (like the shooter, and Fred Phelps, and televangelist millionaires too numerous to name) hate.
All Christians aren't weirdos. Some...many, in fact, are quite liberal minded. (Liberal in the classic sense of the word, not the current political sense). That kind of had to happen as people became more educated, and probably more directly as women gained more equality. You won't hear too many Christians anymore condemn women for working outside of the home, for example. In fact, truth be told, most churches pretty much only survive because of women, who are now generally more active than men.
Services have even changed, and involve more music than preaching in many denominations. I'm not a churchgoer, though when asked for special things, I will go to show support for youth music programs (churches offer more opportunity for youth music programs than schools now, and I personally feel that music is important--and youth perform *gasp* MODERN music). Really, everything has changed drastically since I stopped going years and years ago.
Locally, there was even concern when churches tried to get involved in politics. One church tried, desperately...it was over a GSA club in high school. I live in the Bible Belt. The church failed, miserably. BECAUSE other churches got actively involved to support ALL students, and to condemn hatred. So here, I've seen it. I've seen Christians stand up against Christians. Maybe you aren't looking in the right places.