The 43-year-old NBA champ went on an all-time rant this week ... eviscerating hoop fans for criticizing his unique jumper and demanding some damn respect.

Marion made his fiery comments in a Twitter Space that was discussing the topic, "Who WOULD'VE been the GOAT, if they had more help?" ... after, apparently, someone clowned him over his unorthodox stroke.

And he didn't hold back.

"They talk about my motherf***ing shot," Marion said. "Don't nobody in the f***ing league shoot the same. Get the f*** out of here."

"I'm shooting 35-40% from the f***ing 3-point line at one point in my career," Marion added. "I was a very consistent jump shooter, so you want to sit there and tell me you want to talk about my motherf***ing shot, but don't want to talk about everything else I do on the f***ing floor?"

"Get the f*** out of here. Suck my d***. Like, seriously."

The Matrix went on to list his accolades throughout his 16-year career ... and he's got a point -- the dude is a 4-time All-Star, 2-time All-NBA and scored 17,700 points and grabbed 10,101 rebounds while suiting up for the Phoenix Suns, Miami Heat, Toronto Raptors, Dallas Mavericks and Cleveland Cavaliers.

Marion has been passionately defensive of weird jumpers in the past -- he gave some solid advice to Lonzo Ball via TMZ Sports back in 2017 ... after the young hooper was getting crap for his own shot at the time.