Even though there are traits that all posses no matter when it comes to online pvp type games, there is some type of difference that is perceived between NA and EU... And i do think this comes from both sides. Something else that i think is connected is that i have seen that very few NA people are willing to negotiate in strat with EU, and it is highly unforgivable to do so. I do believe that hospitaller was kind of "outcast" from a subset of NA culture because of their EU associations, and that there is a very bland and unformed power dynamic between NA and EU, whereby the only real option is fight.
That being said the main point of all of this is to say that....
What NA say doesn't really matter, cuz EU has all the players, right? Anyone have the numbers break down?
If I recall, there was once a poll pertaining to strat asking players to select which server they played on. The result of the poll was very nearly one-third voting NA and the rest voting EU. Not sure where that thread went...
Anyhow, I think you're misinterpreting the NA-side's dealings with EU. The problems are underpinned by the map divide, where one third of the map's territories were allotted to the NA strat server and two thirds to the EU strat server. It's not that we're unwilling to negotiate with EU, it's that there are certain power blocs that formed which most of players on the NA side of the map specifically do not like diplomatically, or do not want to have to deal with. By "power blocs" I actually refer to just one bloc who incidentally controls (I think) 100% of the EU side of the map. Several of the smaller EU factions have been forced off of their own side, and so are now on the NA side of the map. NA is very willing to negotiate with them, obviously, because they've taken up quite a bit of NA territory by this point, and NA wanted them there. These EU players share the NA players' feelings towards the aforementioned EU-side bloc, and now everybody is holding hands over here in NA because of shared feelings (and maybe other things, I guess).
NA did stay on its side of the map with relative uniformity, though. I can't think of any instance where NA factions crossed the border with hostile intent, for example. We did, in the past, have dealings and trade routes established with some folks on the EU-side, but either all of those EU people have since lost their territory, or were the ones in control now with whom all of NA is kind-of-sort-of at war with. Before the split map was implemented, in strat 2.0, for example, things were very different, since factions were not forced to one side by rule of design. There was a bit more mixing of sides then.
As for the Hospitallers, I'm not sure what you mean by "outcast" because I'm not sure to which time period you're referring. If you mean when they had their trade agreements with the EU clans who came across the border aggressively to attack NA clans, then, yeah, I guess that caused some grief among the NA community, but it wasn't purely because they were aiding EU, but because they were aiding the particular factions who were removing all of the rest of the NA clans from the NA territories.
The only thing I'll say here about Europeans vs North Americans in a more general sense is that when NA players go to EU servers, they get called out for being there. We even get called cheeseburgers, fat, fat americans, amerifats, and other things like that. I can't think of a single time I saw someone from NA call out an EU player or announce their presence solely because they were from EU, with the exception of strat battles. Usually our trashtalking of EU guys occurs when they're not around.