Stephen Colbert gave the weirdest apology/non-apology in recent memory ... sort of walking back his presidential male-on-male oral sex joke ... seemingly saying gay men who partake are "American Heroes."

Colbert was criticized by some who felt his remark during Monday night's monologue -- "The only thing your mouth [Trump's] is good for is being Vladimir Putin's cock holster" -- was homophobic.

Colbert began Wednesday night's monologue by saying he had "no regrets" about his rant and he'd do it again, but then he walked it back.