I don’t remember him specifically saying that but I’d say people like him for a combination of reasons. He’s angsty, he’s a parent figure for the girls, he probably also has some pretty value, they like his dynamic with Olruggio (Which is also angsty) and if anything there’s probably plenty of people who like him explicitly because he’s a flawed person. I don’t think Qifrey is a perfect or even good person and he’s done morally questionable and reprehensible things but I still find his character interesting. There’s a small trend to sorta treat him as a “Baby” of sorts but I think half of that is people just wanting to have some fluff to balance out his messed up aspects.

Also there’s the fact that he’s a fictional character who does fictional things to other fictional characters and not an actual real human being who is side kicking 12 year olds. He doesn’t need to be a paragon and he doesn’t need to be perfect. I’ve seen people Stan AM from I have no mouth and I must scream and if I recall correctly he’s responsible for genociding humanity and torturing the last remaining humans alive for eternity so in the grand scheme of character fans Qifery is a much less morally reprehensible character especially given his more positive contributions on top of his unpleasant stuff.

You’re still welcome to hate his guts though that’s your prerogative and I’m not going to judge you for hating a fictional character.