Mathematically, they can still win the league I think Rooney is just paying respects to Arsenal, while trying to make some of the Arsenal players get a bit too confident.
This. Also avoiding complacency. Managers and players always seem unwilling to write off their opponents, probably for fear they'll sound too arrogant if they then lose. Didn't AVB say he still thought Liverpool could challenge for the title back when they played Chelsea? That must've been one hell of a speedball
PR talk? Rooney's basically saying that as to not look arrogant. If he actually believes that he needs his head checked.
Definitely will be PR talk. Rooney probably said it just show a little respect to Arsenal, but no way does he really think Arsenal can win the league.