Until now all the swearing the fifth espada has made I didn't find it at any moment out of context. I think it is natural, hell, I would also swear as much if I were fighting a character like Kenpachi. He is the type that pisses you off, just because Tousen didn't do it( he is more classy) Noi is the typical guy that 90% of his conversation have swears in it.
Also not swearing at all would be un-realistic. And before someone says something about: "Bleach is not realistic" or "It is just a manga, don't think so much about it" well when I read mangas I LIKE it even if it is the most un-realistic manga of all times, to have somethings coherent and adequate for the situation.