With emphasis, no, it’s shitty people who happen to be atheist who are the problem. :) Just to clarify, because I would never make that first statement.
“the silliest thing to claim without evidence or explanation of any sort”
You are right, I left a lot implied because my sentiment is a fairly common one. But fair to point out—my apologies. Here is a citation showing that I am far from the first person to hold this opinion on r/atheism.
Note again that I don’t hold any prejudice against any belief system; I only hold that r/atheism in particular historically fostered a culture of toxicity which makes anti-religious prejudice and personal attacks more common compared to offline spaces.