Honestly, stop trolling now. He dressed up as Lil Wayne for Halloween.
You can’t in good faith say he did that as Lil Wayne’s biggest fan.
Instead, he did it to mock Lil Wayne through exaggeration and caricature. Wearing blackface is hurtful because it was — and is — used to create a caricature of Black Americans, exaggerating the Black form and reinforcing racist perceptions.
He knew what he was doing and didn’t care.
If you would like to learn more about blackface, and I suggest you do, there’s a good article here.
This is also common with just being a woman. Womens’ experiences and feelings in general aren’t valued or taken seriously.