Because he's a stupid piece of shit.
More specifically..
He thought I was some poster from NDN or some other board...told him I wasn't...he insisted I was... Lehigh jumped in and said he was familiar with the other poster and me and that we weren't the same person, in that post he mentioned me being a retired Marine... irishshart took this as his cue to switch from accusing me of being the other poster and started questioning my service, saying I was lying, challenging me to Marine knowledge checks, accused me of stolen valor (blah blah blah), then while repeatedly stating I wasn't a Marine he claimed that he was in fact a former Marine grunt...I challenged him to some Marine knowledge which he coincidentally ignored...words were exchanged, then I was done with him but he went into stalker mode literally replying to any post I made (that were football related conversations not mentioning him at all) attacking me every time I spoke, hijacking conversations that had nothing to do with him...I went on the attack...we exchanged for a while...he pulled a bitch move and offered a fake olive branch...I conditionally accepted (suspecting it was BS)...then he went right back on the attack, because he's too stupid for peace ...
so now, Fuck That Guy.
I wouldn't piss on him if he was on fire.