I believe the guests. They were innocent victims of a seriously disturbed individual 
Dogfood Man did other strange things and genuinely believed he had legitimate grievances against people who objected.
None of the women liked him because he was condescending and creepy - not the pocket billiard player, someone else. Christ, I've worked with some charmers. 
The husband thought we were being meanies and Dogfood Man was just a bit awkward so invited him for dinner. Dogfood man returned the invitation. The wife wasn't that keen because he'd been weird to her all evening but her husband persuaded her to go to be nice.
Husband was known for his ridiculously overdeveloped social conscience. He'd taken Dogfood Man to other events - male things like gigs and football. Even though these would end in a disproportionately high number of 'misunderstandings' between Dogfood Man and other patrons, my colleague thought Dogfood Man just had an unfortunate manner.
Dogfood Man probably thought the wife needed taking down a peg or two. Not that she ever went on about her achievements. We only used to see her at the odd office party anyway. It was her husband who used to rave about her cooking.
I wouldn't have liked to be him in the taxi home 