Because he's a fraud
Also Fraudbull should be bottom
How's Law a fraud, exactly?
Defeats a Yonko doing the majority of work, gets jumped by another Yonko and, despite having a subpar, albeit cool, crew, still manages to fight back in good fashion.
Meanwhile Kid gets hard carried against Big Mom, tries to talk shit all the time still, gets clowned by Luffy when their bounties are revealed, decides to jump on Shanks, gets obliterated, his crewmate, who was mocking sanji for asking for help in Onigashima, begs to Shanks to spare Kid's life, then loses his precious ship named after his childhood friend.
There are LEVELS to this, you know?