Politics ain't the only thing Johnny Damon and Donald Trump agree on ... the former MLB star tells TMZ Sports POTUS is right when it comes to Pete Rose's Hall of Fame candidacy as well.

Trump took to his Truth Social page on Friday night to demand MLB "get off its fat, lazy ass" and put Rose into Cooperstown ... and when we spoke with Damon about the opinion on Monday, he told us he concurred.

The ex-Red Sox outfielder -- who actually served on the President's Council on Sports, Fitness and Nutrition during Trump's first term in D.C. -- said the game's climate has changed so much since Rose was first given a perma-ban for gambling on baseball that he now thinks it's about time to get the MLB's Hit King into the HOF.

"I know he made a mistake at one time and it's been so long and now all these baseball teams, they have these gambling sites that sponsor the teams," Damon told us. "I don't think Pete Rose did as much as what's going on right now."

Damon argued, too, that what Rose did wasn't all that unforgiveable -- noting he only "bet on his team to win."

"At least he didn't bet on his team to lose," Damon said.

When he's not advocating for legends to get HOF plaques, Damon's been keeping busy these days working on his A-GAME beverage biz ... and he tells us he thinks it's poised for a big year -- just like the L.A. Dodgers.