It's not weird to support an individual, the question is whether the same level of tribalism should be considered normal. The difference being that a team will last your lifetime whereas a player's career won't. I understand it when it's Spaniards supporting Nadal because what they're really supporting is their country, which again is a lifetime deal.
I completely understand how Spaniards support Rafa - they're from the same country. Its slightly different from team sport where you're basically supporting the ethos of a club that's comprised of players from many different nations.