Hmm, I never heard that Hoffman thing. But, in all fairness, After that tidbit you now have to relay the story to us born after 1970.
Hoffman tried to grab the microphone from Daltrey during the Who's performance at Woodstock and Pete hit Abbie with his guitar and kicked him off the stage, to the cheers of the crowd.
Just as The Who were about to break into their next song, Hoffman ran up to the microphone and started whining about how John Sinclair, the MC5's communist manager, was in prison for dealing drugs.
Townshend was enraged that this filthy loser he never met had interrupted his set and he shouted "F*** off! Get the f*** off my f***ing stage!" and smacked Hoffman upside the head with his guitar.