Don't villanize Wayne Rooney after his drunk driving arrest -- he's a good dude -- so says Rod Stewart

The British rock legend -- who's a HUUUGE soccer fan -- was leaving Catch in L.A. over the weekend when we asked about the biggest football news in the U.K. ... Rooney's DUI arrest in England. 

"He's been a great English football [player] and we all make mistakes," Stewart said ... "And he's still a great guy. A great influence on all the youngsters."

Rooney was busted early Friday morning when he was pulled over in a VW Beetle and failed a breathalyzer. 

According to reports, the Everton striker's bosses are pissed -- and he could get hit with a $415,000 fine over the incident.