It was not me that hit him ( he was several rows in front of me) the guy did tell him to stfu and he gave him a tirade of abuse, so he decked him. As I say we are not going to agree over this.
Yes, I know it wasn't you!
And now that you've actually told the full story, it's perfectly clear that this fella wasn't attacked because he cheered the pitch invader at all but rather because he mouthed off to the wrong person. Which is altogether different. So we don't need to disagree at all.
I still don't think it's worth resorting to violence over a few verbals, mind - even if for no other reason than that the person responsible might well find himself banned from football if seen by stewards or CCTV.