Michael Sam EXPLODED on a guy outside of a West Hollywood club last night -- saying he gives "our community a bad f***ing name" ... and warning him he was about to catch an asswhoopin'.
It all went down outside of Bootsy Bellows, where the ex-football player (who's still in massive, athletic shape) had been hanging out with a group of friends, including E.J. Johnson.
But when they got to the cars, Sam and a man in a white shirt began to yell at each other.
"People like f***ing you give our community a bad f***ing name," Sam roared .