Do you assume that just because someone has a dps meter that they will do this? If so, that’s like saying “Oh wow, you’re not a Christian? So you can just go murder people and steal stuff because you don’t believe in hell?”
People probably do berate people for low damage, but you will probably be with a person or two that has heirlooms to make up for it.
Parsing damage can also lead to some teachable moments and guidance if the players are willing to help the poor damage person.
Harassment is not ok and you will probably get in trouble of you are calling names, being excessively rude, etc. But if you say “hey man your dps is low what are you doing? What abilities are you using? Can you try something new?” Etc. aint bad. And if they don’t respond, either go on about your day, leave, or vote to kick them for being bad. Either way, problem solved. There’s plenty of ways around it without being rude and I’ve played for a long time and never been harassed or harassed anyone for their dps… vOv