Well, that's if the icecaps melted gradually. The topic we've been discussing is a sudden alteration. If we suddenly nuked or "heat-bombed" Antarctica into oblivion, that's a giant change to make the the planet's structure. That's displacing an entire continent worth of ice. That would cause worldwide tidal waves, and probably somewhere along the lines of 90% of Earth's inhabitants wouldn't survive it.

Granted, if the world did flood due to gradual melting, there certainly would be some land left, not much, but some. But, we were talking about instantaneous decimation of the polar icecaps, and that's a much more apocalyptic event to consider.