Ryan Garcia might be causing a ruckus on the internet, but there's one guy who's sticking by his side no matter what -- 'cause Canelo Alvarez tells TMZ Sports he's got the young superstar's back amid his bizarre social media antics.

"You know, he's a good kid and we don't need to judge him," Canelo told TMZ Sports. "He's a good kid and this is the moment when you need to support your friends and, I know, we have a lot of issues before but ... I don't care."

Of course, Ryan has been making a ton of noise leading up to his April 20 fight against Devin Haney ... spewing wild conspiracies and promising free BBLs -- among other wild proclamations.

Canelo isn't distancing himself from Ryan, however -- telling us the Golden Boy mega-fighter will be just fine.

In fact, Canelo says he knows Ryan as a person ... and knows despite what it looks like, he is well aware of what the King is like deep down.

"This is a moment when you need to support your friends," Canelo added.