Fresh off his controversial return on SmackDown last week, the WWE legend joined "The Pat McAfee Show" to address his decision to get back in the squared-circle ... as well as the criticism he's gotten for seemingly stealing the American Nightmare's thunder.

As we previously reported, a TON of wrestling fans are super pissed ... with the belief being Rock is boxing out Cody from a hyped-up match with Reigns at WrestleMania.

Rock made it clear nothing is set in stone in regard to the three moving pieces ... and while he has great respect for Rhodes, his family and his fans -- he feels the exact opposite about the annoying backers he refers to as "Cody crybabies."

The actor mocked the "grown ass men" behind the #WeWantCody campaign who are losing their minds over Rhodes' potentially spoiled plans with Reigns ... and it is legitimately classic stuff.

"The Rock says this," Johnson said on the show. "All you gotta do is sit back, know your role, shut your mouth and enjoy the ride that the Rock is gonna take your candy asses on. So hashtag that, hashtag shut your bitch asses up, hashtag Cody crybabies."

As we previously reported, Cody's fans showed him a ton of love on "Raw" earlier this week ... and he just recently revealed he's made his decision on what to do with his WrestleMania match.