I'm not a big Radiohead guy either. Kinda sleepy music at times. It's def not one of his brightest moments either, letting someone in the crowd get to him, but it could be taken another way. He is doing a solo show and playing just solo material with some RH songs, when you get some guy yelling out for him to play other stuff (Skynyrd). So my take is that he thought it was dick and sarcastically came back at they guy, referencing playing some other bands as well (STP). I don't think it's a knock at STP... But who knows, maybe he's dick and thinks STP sucks, in which case then HE SUCKS BALLS.
Also something to note, there was an STP interview in 2000 or 01, maybe Family Values time line, where Scott said they "dig" Radiohead when STP were asked about other bands they currently liked in the music scene.