I didn't say attacks don't happen on reddit. Nor did I say they don't allow them.
I do say that reddit works (in terms of a larger group participating) because folks who are abusive to the point of disrupting the civil on-topic discussions, are stopped from posting disruptive stuff. That leash does seem to be shorter on negative-mvis voices, which is understandable, because the majority of the reddit group is positive-mvis and more bothered by negative-mvis folks.
None of that means reddit mods don't "allow" some attack type comments. They do, in limited amounts/severity, from what they see as valuable contributors. What they don't tolerate, is attack comments from folks who disrupt their board. And yes, it does seem like there is some bias in their moderating.......but that is natural, and to be expected, as I have explained before. (And a reason I prefer an admin monitored board, if it is monitored.) The bottom line is that their board works, better than a board dominated by nonsense (because admins don't have the resources to moderate actively).