what was the reason why malcom x was killed?

Malcolm X believed in fighting oppression with violence, and was shot dead.
ML King believed in fighting oppression with non-violence, and was shot dead.

See the pattern....? 🤔

He was a threat. To many. The Nation of Islam are the ones that decided to do something about it.

For being a leftist political leader with followers.

Probably because he was too close with Lincoln Rockwell and his neo Nazi group. Malcom X and Rockwell were militant but smart. They weren't fighting enough with each other like the establishment wanted. They were starting to spread racial nationalism. Which is a threat to globalism. Rockwell was killed too.