Like if any non-Americans enjoy American leagues (like the NBA) there are tons of welcoming fans who would help with understanding the game and the history/tactics.

That's a bit different though. American sports are usually pretty much american only - here in England we don't really have any decent basketball/american football/baseball/hockey leagues. I honestly know no one who's ever even been to see one of those games over here. So if someone were to be interested in the sport, we'd have to follow an american team.

Footy is an international sport however, and America does have a big league system with well supported teams (don't Seattle get ~45k average or something?). MLS is a really up and coming league with quite a few big names over there so it's a bit strange to literally want to only watch the leagues at the very, very top. I think it's confusing to a lot of us why a lot of americans still persist to shun the MLS and focus on english footy. I don't mind that too much, but it does grind my gears when I see americans making comments about 'scousers' or 'mancs' or try and get involved in a local rivalry when it's something they have no idea about.