Flea -- Rips 'Small-Minded' Critics ... My Nat'l Anthem Was Beautiful'

Flea tells TMZ Sports ... he knows there's been some harsh criticism when it comes to his rendition of the National Anthem at Kobe's farewell game -- but says the critics are just "small-minded" haters.

As we previously reported, Flea's instrumental version of "The Star-Spangled Banner" didn't go over so well with the masses ... the NY Daily News said he may have to go "hide under a bridge."

So, how does Flea feel about it?

"I don't care man," Flea said of the criticism ... "I know that people who liked music liked it. I thought it was beautiful."

He added, "I really don't have any concern for little small minds that get frustrated when they get blown ... I like big minds."