The draft is a cruel tax, but the volunteer army does create a disconnect between the people who are fighting and the people for whom they are fighting.
What are the effects of this "disconnect" supposed to be? Perhaps I'm misreading Arnold, but it sounds like he's concerned that volunteer armies will be more likely to sent off to war because most people know that their kids won't get shot at.
Even if this were true, the soldiers have nothing to complain about ex ante. If we're more likely to send a volunteer army into combat, we'll have to pay volunteers more to compensate for the risk. The main people whose interests aren't being taken into account are not our soldiers, but citizens of countries that might get attacked.
Empirically, though, it seems like volunteer armies discourage war, precisely because the price of recruiting is high, and increases with risk. So the only people who should worry about the draft are those who think we're not taking enough risks as it is.