Yes, because it is not fair. One has a higher chance of dying in the army than from drinking alcohol at the age of 18.
No, because those who are in the army should still be perfectly healthy with no alcohol in their system to serve the army the best that they can.
It makes little difference. And also, most soldiers drink already.
It is. I'm in the UK where the legal age to drink is 18.
You are considered an adult at 18. If you can vote for president you should be able to drink. Either raise the age to vote or lower the age to drink.
Yes, at 21 for distilled beverages.