Many people say here that YTA but im not quite sure.
Ive read once a story on r/ChoosingBeggars a few weeks ago at the time where everyone posted flying stories.
So there was a guy who wore his military outfit and sat in ops seat. He kind of made a show that hes tired and everyone in the plane said to just let him be because he served. I didnt find this ok because youre not entitled to something because you do something freely.
Anyways i jumped into the commentary section and there was a guy who also was in the army and said when he gets home with the plane. He shouldnt wear his uniform because thats just attention seeking and also be a target on a takeover
But maybe the guy in the uniform just didnt have anything else to wear and that was his nicest cloth. Also you said he was well behaved so i dont see there any problems with it on a guest list of 300. Geez do you invited every facebook friend or how do you know so many?
I understand you want attention for your wedding but i wouldnt have thrown him out.
ESH guy for taking his uniform and you for throwing him out at a guest list of 300