The fans don't particularly care that it's owned by an american and sponsored by a UAE airline, because what matters is the coming together of the fans behind a common cause.

The fans do typically come from the area around the stadium in North London.

When you get just a little bit further down the league it's still very much a geographical thing because the teams are less well known and less successful, so are less likely to attract people who want to support "the best team". For example, Southampton FC fans are pretty much exclusively from Southampton.