You really can't compare Fox in Melee to Bayo in Smash 4, Bayo gets hate from the competitive community because:
1. She's by far the best character.
2. She has way too many tools that give her an answer to practically every situation.
3. She's pretty easy to get good at.
4. A combination of all three means she's both awful to play against aswell as watch.
Fox is the best character in Melee, but not by as great a distance as Bayo, he even has some even matchups. He also has by far the highest skill ceiling in the game, which not only means that there's more respect for people who reach the absolute top with him as they've put in a ton of work to get there, but also that they can't always consistently pull off victories in easy or cheap manners. Lastly, a great Fox is just so much fun to watch, he's one of the most entertaining top tier characters in any fighting game.
The competitive community usually doesn't care one bit about a character's origins and who he/she is, the fact of the matter is just that Bayonetta was incredibly oppressive to the Smash 4 meta, which was in an otherwise good place before her. Whether you like Bayo or not it's hard to deny that she needs changes in Ultimate.
I'm not denying that people hated her beforehand though, but the speculation and competitive community is not tied very tightly together.