Harry Potter reached the height of its popularity in the 2000s/early 2010s, in a time when gay was still an extremely popular insult, feminists were the punching bags of the internet, holocaust jokes were a dime a dozen and anyone saying it wasn’t funny was an enemy to comedy itself, the biggest internet creators took literal pride in their content specifically being offensive (Smosh was the biggest example of this IMO), and saying you should respect people’s gender identities on the mainstream internet will get you labeled as an SJW and actual death threats thrown your way, so I’d also argue that Harry Potter not being seen as problematic was in part because mainstream society (not you obviously, but the broader internet/pop culture in general at the time) genuinely did not view those things as problematic. Like if JK Rowling said all the things she said about transgender rights in 2003, she would probably still end up in controversy but way more people would actually support her, would have probably split the fandom roughly down the middle as opposed to the overwhelmingly negative response she’s receiving in the 2020s. Or look at it this way: Harry Potter was most popular in the same time period when Family Guy was most popular.