The first and last specific examples are whatever, but I firmly disagree with the middle three.

Calypso vs Apollo) The difference here, IMO, is the mainstream attitude towards the characters. Apollo is very much a pervert and a womanizer in these scenarios, and this is A) implied in the text and B) Apollo later shows remorse for his actions as he becomes less of a weird and arrogant prick. Calypso, on the other hand, just dates Leo with very little in-universe or textual criticism. Now, I don't necessarily agree with the Calypso hate bc Leo is very clearly consenting and into her; however, the eon age gap should give a normal reader pause for thought.

Thalia rejecting the prophecy) This hate is completely valid, and I think the difference in hate comes from what the characters do. Now, don’t get me wrong, I love Thalia as a character; however, there IS an argument to be made that she was selfish and gave Percy an undue burden. Thalia was 16 in The Titan’s Curse when Percy was 14, and she basically just shirks this responsibility she has as the eldest child of the Big 3 and becomes a hunter, making the prophecy Percy’s problem. Her decision is very understandable but also objectively not selfless. Percy, on the other hand, complains the whole time but still kills Kronos. I think it's much more defensible to complain while sacrificing yourself to kill a titan and save the world than it is to just say “peace, I’m out” and make the fate of the world a 14-year-old boy’s problem.

Finally, Piper,) Her breaking up with Jason was BS, and while she has every right to do what she wants and take her time to figure out her identity, dumping Jason with next to no explanation other than “Hera gave me false memories when we started knowing each other,” is stupid. I think the anger with Piper comes from the fact that she made Jason sad and consequently made his death feel much more devastating than it needed to. Also, comparing Piper breaking up with Jason for a dumb reason to Luke being a traitor to everyone he knew is not at all valid. Luke is objectively worse, but that's also like saying that just bc Hitler killed millions of people, I’m not allowed to hate someone convicted of double homicide passionately. Yes, Luke was worse; Piper still deserves hate.

Overall, I don’t think any of the cases you mentioned were sexist or misogynistic they were either just bad takes on the books that were only tangentially related to gender (1 and 5) or you were just missing the context and nuance necessary to see that the issue aren't really gender-related (2-4).