If a bunch of clowns want to brand STID as the worst ST film ever (Which it just isn't by any measure, however you feel about it) then why not tell them to go f*ck themselves. Hardly the end of the world. People need a sense of humour sometimes.
Also Simon is a HUGE SW fan, always has been just like you and me. I hate what was done in the PT also but I'd still jump at the chance of being involved in some level (Not that anybody would ask me to do a voice lol). Nothing hypocritical about that.
Plus just for that hilarious scene from Spaced where Simon burns all his SW memorabilia after seeing TPM (Perfectly capturing the pain of a generation) means I'll forgive him almost anything ;-) *
(* Maybe not his performance as Scotty)