9:20 AM PT -- J.D. tells TMZ Sports he meant Kaep was screwing up the owners' money, not the money for black QBs.

Colin Kaepernick's protest is screwing up the NFL ecosystem for black QBs and costing them major money ... so says "The Wire" actor J.D. Williams who says Colin's hurting more than he's helping.

Williams has been in a ton of stuff, but he's most famous for playing street soldier Bodie Broadus for four seasons on HBO's "The Wire."

Williams took to his Twitter moments ago and fired off a series of tweets doing something most black celebrities have shied away from doing ... criticizing Colin Kaepernick's protest.

"I appreciate Kaepernicks' sentiment and attempt at a statement but he didn't HAVE to sacrifice his career in THAT way. Nice try?"

"We do REMEMBER black QBs in the NFL weren't even a THING really until about 7 yrs ago right? Kaep f**ked up their money ... with a big ass fro."

He didn't stop there, going on to imply Colin's protest wasn't a smart thing to do, because his employer (the NFL) doesn't care about his politics.