I agree with OP, it’s not really confirmation bias. I’ve been playing for 8 months now and never did I witness toxic behaviour in dungeons or random raids, not even after wiping several times. In WoW it’s normal behaviour to point fingers at others, drop some annoyed comments or straightup insult others.
And that’s good, because dmg meters aren’t allowed anyway.
From time to time there are some gems in the community, but come on, that’s not the norm.