Attacks committed under the banners of Christianity and Islam aren't handled in the same way by either side. No, those on the left don't jump at the chance to shout #notallchristians every time a right-wing white guy does something, but 1.) Christians in this country aren't a small minority, and 2.) folks on the right aren't constantly looking for ways to demonize them.
At least in the US, anti-Muslim bigotry is a very easy thing to trigger, partly because many folks in the media seek to profit off of it. This isn't just a fringe element of the right-wing; it's popular media personalities and
people at the highest level of politics stoking fires ready to flare up almost anywhere. Off the top of my head, I can think protests and political/legal fights against the "9/11 mosque", another mosque in Murfreesboro, and against a Muslim cemetery in central MA - none of which had anything to do with terrorism and everything to do with blind religious bigotry. And then there was all the Muslim-related stuff thrown at Obama. Given that volatility and the fact that the bigotry is directed at a small minority, I don't think it's inappropriate to be constantly vigilant against allowing it to get out of hand.