Pretty sure it's just as obvious that religiously motivated terrorism is bad. What was your plan here? Show up with signs that say "We oppose the killing of innocent people in the name of God"? My response to that would be "well,
duh."
I mean, sure, you'd probably get some people telling you that Islam has nothing to do with terrorism and "they're perverting a religion of peace" and all of that schtick. I assume that's what you're suggesting and I suspect that would indeed happen... But other than deliberately provoking that reaction, what was the purpose of the demonstration in the first place?