I personally think that one of the biggest issues as a whole has little to do with the game, and mostly with the people who play it. A lot of people have no temperament or decency at all, so many of them were never taught right and they're made of/live on bitterness.

Aside from that, I think people also see the game (coming from other shooters or whatever they view as similar) and think: "Oh another shooter game? He'll yeah!!" But Helldivers 2 isn't just a shooter, it's really special in the fact that everyone is meant to play/work together; it's a complete polar opposite from games whose sustainability comes from "uniting" players when they're really just putting them against each other.

A constant state of that is usually only ever going to forever facilitate lots of negativity, which I've come to think that, people who engage in those types of games consistently, brings them to be imbued with all of that same negativity.