What's your reasoning here? The purpose of the military is to defend valuables from others. Deploying military to Mars is as likely as deploying military to the Antarctic.
Scientists will be the first and probably last to occupy. Difficult to imagine it will ever expand much beyond research missions. The Antarctic environment is far less harsh than Mars and no-one maintains a permanent base there.
That's completely incorrect. While a lot of the workers in the Antarctic program (I wintered over in 2016 as a station Network Engineer) go on to work at NASA, because of environmental similarities to space/Mars/etc, many countries maintain permanent research stations in Antarctica. The personnel switch out every season, but the bases are permanent.
Nobody is suggesting we colonise the Antarctic, because there's nothing much (of current economic value) there. There are a handful of people there to study it and they need a constant supply of resources to sustain them. If that was the point of going to Mars, then you'd really have to question what can be achieved there that warrants such massive cost, especially if any part of that cost is government funded.
Now, if we contrast that with the Arctic, the first sign of a melting ice cap and there's military posturing over who is going to exploit the natural resources being exposed there.
As Antarctica has never been permanently settled by humans, there has historically been little military activity in the Antarctic. Because the Antarctic Treaty, which came into effect on June 23, 1961, bans military activity in Antarctica, military personnel and equipment may only be used for scientific research or any other peaceful purpose (such as delivering supplies) on the continent.