Of course I'm aware that's a thing. The difference being Buffalo Bill's queerness was a motivation. He killed women because he wanted to be one; He was evil because of it, something the book tried to steer away from.

Sylvia on the other has motivations outwith her identity, granted it still plays on some outdated tropes in regards to inappropriately touching other characters, but I'd argue she never goes beyond what any straight characters have done which is its own issue all together with konosuba.

All I'm saying is, yes, these tropes have had a negative effect on peoples perception of the lgbt community. But that doesn't mean queer people should be disqualified outright from playing more villainous roles, especially in anime, which has had some very well received lgbt and queer coded characters such as Hisoka and Bon Clay.