Interesting point. Slightly OT but: how far should you go? I don't write "favor" or "humor" just as I don't put on an American accent, but it's fair enough to adapt one's language when it's part of the game. So I do write "defense" or "offense", and I'm happy to put the home team last when we're talking about scores. But I can't bring myself to say that a player went "off-sides" or to say "road game".
As for becoming a Patriots fan, it's simple enough. I lived in New England for a year. The Patriots were terrible and all of my American friends were fans of much more successful teams (Cowboys, Raiders -- even the Jets and the Rams). So I could root for a team without being accused of being a bandwagon fan. Then came the miracle of the Krafts and Bill Belichick. And now I live in New England again ...