Who is in the wrong

My boyfriend (Jack) went to a party for his best friends Daniel’s birthday and so did my sisters boyfriend. After my sister picked her boyfriend up she rang me and told me that her boyfriend saw one girl (Stacey) crying because a guy (Anthony) suddenly put her into a chokehold, playing it off as a joke - The girl is Daniel’s girlfriend.

I have a friend who’s boyfriend was good friends with Anthony 5 odd years ago and she’s basically hated him for years.. I can’t really remember why but there were also rumours he would beat his ex girlfriend.. I had never met him until I met my boyfriend Jack, though. When I initially met him he was fine and I wondered what my friends issue was. He was switched on, calm and normal. But then a bunch of us went bowling and when he got a few beers in him he completely switched. He was blatantly intimidating the other families and groups next to us. When we all gathered in the car park to leave he was just acting staunch, intimidating others driving through and tried to intimidate me about the car I drive. We went to a pub after and he eventually got kicked out after trying to fight a random patron and swearing at the bar staff.

Back to the party last night.. my boyfriend Jack didn’t get home till later and he was upset. I asked what happened and he told me he hit Anthony. I forgot about the incident and was upset with him but when he told me what happened, he said an hour or so after my sisters boyfriend left Stacey was still extremely upset and he just kept saying “you shouldn’t have seen her eyes”. He grew up around family violence and he doesn’t take it lightly, and was upset that all the guys didn’t kick him out, likely because they’re all intimidated by him, only whispering about what happened while Emily was still visibly upset and Anthony was walking around the house all staunch. So, Jack went up to him and told him (aggressively I will say) that he needed to leave and then he hit him. The fight only lasted for a moment in time and then soon later Anthony’s girlfriend picked him up. Jack put him into the car and apologised but said it needed to be done and his girlfriend was pissed off with him too.

Who is in the wrong here?