FOOL FIGHTERS TMZSports.com
Dave Portnoy is a big fan of Dave Grohl ... but he can't wrap his head around why the Foo Fighters frontman would pick a fight with Taylor Swift -- telling TMZ Sports he believes the pop superstar is the real deal on the stage.
The Barstool Sports founder -- who is very vocal about his love for T-Swift -- weighed in on the music industry's newest beef this week ... and he said going after the Swifties' "mother" is a fuse you don't want to light in the first place, but especially when it's over her performance skills.