That's only one reason, though I do admit I never root for anyone I find repulsive of face. But, I'll admit I like good looking players.
I also like his passion, his excitement, his originality, his humbleness, his warriorlike spirit, his never disparaging opponents, his smile, his going to other players to settle disputes instead of talking about them to the press, the way he wears bright colors, the way he hits the ball, the way he moves around the court, the way he always knew he was good and didn't need anyone to pump him up, the way he's close to his family, the way he plays in Mallorca, the way he parades his girl around, the way he's committed to Davis Cup, the way he seems like a kid, the way he's so respectful. Those are just a few of the reasons I like him, but it's easier to lump it all into cute.