It is objectively poorly written and poorly constructed. That's not really up for debate. The idea that it's acceptable for small children is it's only saving grace. Any adult who likes it is blinded by nostalgia or has built a personality around it.
I "grew up" with it. I read them as they came out as I was about the age. It was known to be slop for children back then.
It's not a binary from bad to acceptable. There's A LOT of range in YA books and a lot of good ones. Rowlings issue is so fundamental it really would prevent her from writing any kind of book. She simply packed the knowledge about writing to do any amount of planning ahead. She's constantly pulling out a McGuffin and insulting the intelligence of her readers. There's no thought put into the world. The characters don't come to life. It has the sensibility of Willy Wonka and the set design by Tim Burton. Her writing is closer to a single stream of consciousness than a deliberate plot because she lacked, and probably still lacks, the literary skill or expertise to actually craft that.
Her success is entirely due to factors outside her control and is in spite of her characteristic lack of ability.
Also; Tom Clancy sucks. In fact, Tom Clancy <<< Clive Cussler- and Cussler is mediocre at best.
People programmed in terrible ways are terrible. Mourn their death and move on.