Killer Mike, T.I., Young Thug, Fat Joe, and more also filed a brief arguing that the lyrics were used to "stoke racial and anti-rap bias"

Killer Mike, Travis Scott, T.I. and other artists said James Broadnax was sent to death row in Texas based partly on his artistic expression.

Killer Mike says he's tired of watching poor kids fight wars ... arguing countries that want to go to war should send entitled rich kids instead. We caught up with the four-time Grammy winner at LAX Thursday ... and we had to ask the politically…