I read this article and it really annoyed me. The author is mostly right, but they have missed a huge chunk of context!
First of all JKR wrote the first few books while in, or directly recovering from, an abusive relationship. Usually if you've had that experience, it is all tied up in unhealthy relationship beliefs, unhealthy beliefs about what "all men" are like, human nature, male/female nature and so on. When I look back at various bits of creative writing I did back when I had those kinds of beliefs myself, I cringe at how I portrayed normal/acceptable relationships - it really speaks volumes. JKR is human, she has human experiences, she is not perfect.
Secondly, she didn't write Cursed Child. So there would be no reason/scope for her to change the character of Ron, or include a divorce storyline, because it wasn't her story, it just took place in her world. And the plot of the Cursed Child was about something totally different so it wouldn't make sense for R &H to have a little background plot of divorce procedures, it would be distracting from the story the playwright wanted to tell.
Thirdly, just because her book is popular among adolescents, does it have to be a perfect educational resource with everyone behaving in a way we'd ideally like to emulate? That is a ridiculous assertation and one that would make literature bland in the extreme.
If you read her more recent books such at the Cormoran Strike series, you can see there's been an incredible amount of growth and development in terms of her understanding of relationship nuance. (Without wanting to give spoilers) she manages to portray characters going through and moving on from unhealthy relationships in a very believable and relatable way.
Should we talk about Ron and Hermione's relationship? YES! Should the books have been written differently? Absolutely not.