You didn't really answer the question.
Look, I'll be the first to say that a bad day at the beach beats a nice day at the office. But the GM doesn't want what appears to be a fairly by the book FR campaign.
You had suggested
Yes. That is what the GM had tried to do. A human-only GOT campaign. Which is something that P4 would not enjoy. At the same time, P4's suggested modifications to the campaign wouldn't be something that the GM would enjoy. So why force one upon the other?
GM should be able to say, "Yeah, I get that's what you want to play but that's not the kind of campaign I'm looking to run right now. It's probably not going to be a good fit. But hey, when I'm done with this campaign, can I give you a holler?"
It comes down to tact and communication. There may have been some kind of communication breakdown here leading to flared tempers and wounded pride.