The problem was joining a "military RP" in the first place.
Please don't say things like that, even if they are your opinion.
You might as well be dismissing the topic. The problem isn't the server type here at all, it's just the way OP and the server admin's acted/spoke towards each other.
This is one of those drama where both parties are to blame.
A half backfire.
This.
Seems OP was kind of rude to just join the server and start asking if it's a "sissy ass rp". It implies that is what you think it is like, and isn't very respectful. It could also be read as if you're calling all Roleplays "sissy ass". Which obviously isn't something the host of a Roleplay server wants to hear.
You could've asked in a nicer tone what the roleplay was like.
But it seems Gunnery Sergeant was being a bit awkward and slightly unfair in banning you for a normal comment that wasn't a complaint, assuming what you claim to have said is true.
I don't know if it was just a big misunderstanding based off of the way you joined the server, but it sounds like all parties involved got a bit too heated and argumentative.