I can believe it - reading some of the comments on various message boards, there seems to be plenty of normal Leeds fans ashamed and appalled by what went on. Be nice to think a few fair-minded folk gave the knuckleheads a pop.
This for example http://www.barnsleyfc.org.uk/BBS/forums/thread-view.asp?tid=71402&mid=448249#M448249
The fans in the stands were chanting "Elland Road scum, Elland Rd scum" at those who had run on the pitch. Some of those then running back off the field were then apparently set upon.