First declaration of principles: I'm a Röyals fan, first, last, and always.
But I don't support any particular team in the National League. Would it be ethical for me to adopt the Rockies as my NL team if I freely admit I'm bandwagoning?
Of course, if the Röyals faced the Rockies, I would unhesitatingly root 100% for the Röyals. But this Rockies team looks interesting, and it's definitely more fun to follow a sport if you're rooting for one of the teams. I barely follow the National League right now, and if I had a rooting interest I would gain overall baseball enjoyment.
An analogy would be soccer. My team is FC Barcelona, first, last, and always, win or lose, rain or shine, even though they took money from the Qatar Foundation to emblazon their name on their jerseys for next season. But in the EPL I'm an Arsenal supporter because I have a friend from London whose team is Arsenal, and we occasionally watch the games together. The EPL is a great league, and it's more fun if you're backing one of the teams.
If Arsenal wins, I think, "Well, good." If they lose I think, "Well, bummer." I don't get all excited either way, but I'm happy if they do well. Naturally, when Barça plays Arsenal I'm for Barça 100%.
So can I adopt the Rockies as my NL team, provided that 1) I do not betray the Röyals 2) I stick with the decision whether they're good or bad 3) I admit I'm a bandwagoner 4) I do not excessively celebrate any Rockies' success?