Yes it is, a good team should be able to win at home and especially on the road. This is where veteran experience comes in. Doesnt matter if you're missing one of your best players or not, Both celtics and spurs have been playing a while without KG and Ginobilli, they should have came up with plan B by now and if they didnt, then they miss out oh well..no one said life would be fair, they both had their shots at championships, they should let others try!
Oh yea and just an FYI, Mavs won against the spurs the last time they faced each other in playoffs in 2006 and they had Ginobili then! It went to 7 games but the Mavs still came on top!