If you want to play with less hostile folks, I would highly recommend learning basic Japanese and playing on a Japanese server.
Even if you don't speak it well, it seems like most people will try to switch to English to explain something to you, instead of becoming angry.
I had someone tell me about 制限削除. I understand what it means (Removing restrictions), but I didn't know what the English equivalent was in the game (Undersized Party). Pretty different, right?

Because I didn't know about that option, he tried really hard in poor English to explain it me. I was really grateful, but in the end I had to Google it because I didn't know an undersized party option even existed.

I have never seen a Japanese player being aggressively hostile to another player in any party (yet). (But I have seen an annoyed healer stop healing once, without saying anything).

The most hostile thing I've ever seen a Japanese player say, was when they called the members of an opposing Grand Company idiots during PvP (even though they can't see it).

Now, English players I've been with are a totally different story! I've been in a few groups with English players who are downright mean, cruel bullies who swear and flip out at the slightest mistake of another player.