I didn't watch the event and wasn't there, but from what I've gathered this morning:

That's Sean Strickland, a 💰UFC💰 fighter and he's been pretty vocally anti-Israel and still thinks the Epstein files are a big deal. Unsure on his feelings towards Trump specifically anymore (previous MAGA I believe) but he was in some way discouraged from attending this event because of his outspokenness about Israel and Epstein.

He showed up anyway (not wearing the shirt in the image, that's fake afaik) and got some sort of fighting pit started with fans where he was lightly sparring with people and it caused a crowd to start forming. That's when security/police stepped in to escort him out.

The man pictured being arrested is Sean Strickland, a current champion of his weight class in the UFC. He was supposed to attend the event as a spectator, but had his invitation revoked about a week ago due to publicly criticizing Israeli genocide and Israel’s control over US politics. (It’s unclear whether Strickland has a meaningful moral compass or if he is simply reading the room and saying what he can for social media engagement, my guess is the latter but that’s aside from the point.) Strickland decided not to waste his flight ticket and went to the event anyway as a form of protest, showed up and started riling the crowd up a bit before the event started, and then got arrested and charged with disorderly conduct.

As someone else pointed out he wasn’t actually wearing the Epstein shirt, but he has criticized the Epstein coverup in addition to Israeli meddling recently.