I don’t think this is a universal or really even “normal” human trait. Even in kids, only some kids behave that way, and they tend to grow out of it, especially by late teens or early 20s (partly because people that age are exploring how ideas work to some extent). Rowling is 54. Further, the more intellectually curious you are, the less likely you seem to be to do this. Whereas the more you value your own pride, your own sense of superiority, and the less empathy you have, the less intellectual curiosity, the more likely you are to do this. It also tends to be a personality trait, and has little relationship to how much you are criticised. If you act like this, even mild criticism will make you defensive and abusive.
Sadly, Rowling has always had this personality trait. You can see it from the early days of Harry Potter, where whenever someone called Harry Potter a fantasy novel, she got angry and said it wasn’t, whilst making wild, sweeping and inaccurate assertions about the fantasy genre (primarily that it was just adventure novels for 13-year-old boys). Likewise when people point out there were similar books before (after Rowling had herself declared that she invented a genre), she was extremely angry and defensive, dismissing other authors and so on. She’s never been intellectually curious either, as you can see from her reading habits (or lack thereof) and general lack of interest in exploring ideas.
Tixy, PragerU is a far-right/ultra-conservative outlet who have no relationship to the facts. Claiming to be rational whilst having to resort to posting their material means it’s not society which has changed, it’s you who have.
They deny that racism, homophobia, hatred of Islam, misogyny and so on are even things. They consistently deny climate change. They frequently use outright white supremacist arguments and logic. They’re directly funded by far-right donors and their content reflects the agendas and interests of those people, and is often presented by pseudo-academics.
Using their material is not compatible with being “rational”. It’s compatible with being on the far-right, and white supremacism and so on.
Also, if you’re hard-against trans rights and perhaps against BLM and so on (as PragerU are), I don’t think you’re likely to find any gaming-related sites at all outside of the fringe-right (parts of 4Chan). Even the most generally right-wing and dismissive mainstream sites (like parts of reddit and RPG Codex) tend to be far to the left of PragerU.