Personally I'd say the only time it can be justified is either in self defence or if you are fucked up enough to take part in organised rucks with like minded retards...
If folk get sum sort of warped buzz out of beatin fuck out of each other let em get on with it, as long as it doesn't involve those of us who have evolved beyond the primeval stage its fine..
It's more of a social defect if anything, football is just an excuse for these types, we all know some knob who has a few jars and gets some deranged urge to hit someone.. dunno why, it's beyond my level of understanding..!
Thankfully nowadays, it's nothin like it was in the 70's mainly cos of cctv.
I've walked through the middle of it and even stepped over bodies outside Maine Rd a few times without being involved, Everton and Brum spring to mind.. only time I had to look after meself was at Norwich of all places! when I had to deliver a swift kick to the solar plexus of a local farmer or summat who decided to have a go in a park on the way back to the car..he took exception to a v.rare Adrian Heath goal in a 1-0 victory.
I perfected a scouse accent for walkin through Stanley Park.. essential for when you got asked the time in the 70's.
I remember the C.Cats tryin to get through barriers to Spurs at Wembley in 81 right next to me, coppers kept em apart and they resorted to gobbin at each other..some where catchin it in their mouths..dirty bastards..!
But the worst was Leeds late 70's where a guy on our coach got kicked senseless protecting his 11 yr old son from the Leeds pricks by lying on top of him, he suffered brain damage and obv was never the same again.
When you see summat like that it gives you the urge for revenge and hence it all goes around.
I take my son to games who now happens to be 11, I couldn't envisage summat like that takin place these days.. Jesus..imagine it, you wouldn't rest till you hunted em down would you..?