Oh please, everyone steals. You steal, I steal, everyone steals. Christ, there's a part in Star Wars, I believe at the beginning of Return of the Jedi that sounds just like the Mystic Circle of Dancers or whatever from the 2nd act of Rite of Spring. That same section is BLATANTLY stolen from Nuages (Debussy) from Stravinsky. Igor did quite a bit of this as we all know, and we still love him. The point is, John Williams is a great composer, a DAMN good film composer and has done much more creative things and seen more success for his creativity than probably any internet schmuck with an opinion ever will.
It's funny, I bet if John Williams, or John Cage or whoever else walked into your room right now you'd all be kissing their asses. Either that, or you'd actually have the audacity of throwing your own scores at them and saying, "gently caress you Cage/Williams/etc, my music's better than yours", then they'd just beat you with their Grammys' and Pulitzers....