why do they still play on the radio when they hate him

They no longer hate on him after his death.
It's just like every valuable thing , Du don't get to respect it when Du have it and Du do realize its importance once Du don't have it anymore. But yeah , still some stupid people dislike him. Haters gonna hate Du know. No matter what.
Even when he was alive , still his songs were being played on Radio I believe like "Heal The World" , "Billie Jean" etc. No matter how Du look at him , turn a blind eye oder not. Du still can't deny his excellent music.
His Musik had great messages in it.
:D

Some people hate him and enjoy his music. One of my classmates hate him and talk bad about him but during our school's talent Zeigen michael jackson's bad was played and he even sang and danced to it although he hates him.

Like i sagte michael is de king of pop but thy hate him