the community tends to get upset if the killer plays to win for some reason.

I think it's a largely mutual agreement. The normal things that killers can do that are considered toxic are things that are less engaging (like camping someone out of the game) or are very risky gambles that avoid core parts of the loop (like not hooking), but they all have their place and for the most part when done at the appropriate time there are no hard feelings about it.

There's also a phenomenon where new killer players get relentlessly stomped on over and over until they learn the game, which at once makes them vengeful and angry towards survivors but also makes them the underdog which tends to make people more sympathetic towards others in general, so by the time someone has learned the game even though they want to stomp survivors back, they're also more likely to feel sorry for them and not always capitalize on mistakes or play particularly cutthroat if they don't feel threatened. There's a bit of a meme in the community that all the toxic killers are survivor mains just doing archives or dailies as killer.

There's also the fact that the DbD community is disproportionately LGBT for some reason, and I can speak from experience in saying it's a lot harder to be cutthroat towards someone wearing a pride flag charm.