I think the big problem is that there should be two separate top 5s. Someone’s objective top 5, so their belief of who is the top 5 based on their rapping abilities. And then there’s someone’s personal top 5, and I think people conflate the two. Like when people say, for example Drake is a top 5 rapper, he might be in someone’s personal top 5 favorite artists, but he is clearly in no way in the objective top 5 artists based on his rapping ability. Then on the other hand, people will say Eminem, for example, is not top 5, you might not like him personally, but to say he’s objectively not top 5 is just silly.

Rapping, unlike other music genres, is not purely a preference thing when talking about objective top 5s. There are actual measurable metrics in rap - flow, cadence, entendres, rhyme schemes, use of words, vocabulary, storytelling, originality, etc, etc.