Part of it is the Lucha mindset, guys have to basically be in Bruiser Brody mode in terms of looking out for themselves to the point it is very off putting to US promoters/wrestlers since we haven't really seen someone like that here since, well, Brody.
That's where stuff like "WWE got mad Sin Cara acts like a big star" comes from. That's where LA Park and his famous difficult to work with stories come from. They came up in a business that is very much still in the "slimy territory promoter" era, so they are more or less taught to be difficult to work with.
Having said all that, if you tend to be an asshole on top of all of that.....well that's where the fun starts.