It isn't a fallacy (and most certainly isn't 'begging the question') -
Of course people have no better means to protect themselves from a large group (security force) than having their own large group to defend.
Fallacy or not, that's just plain false, right there. A professional fighting force is certainly one way to do it, and it would certainly require fewer pros to defend a given area than it would militiamen or the like but "no better means" is pushing it a little bit. Remember "defense in depth"? He didn't say it, but the quote attributed to Adm. Yamamoto holds true: "We can't invade America. There would be a rifle behind every blade of grass." Invading a country with armed citizenry is dangerous. Invading
one where the average citizen might have any weapon you do is suicidal.
And yes, there are people who whether because of religious or philosophical belief, or some other reason will desire someone else to do their defending for them. That's fine. They will be provided for. But even then, it need not be a large group that does it. Perhaps the community bands together, and the pacifist does the bandaging, in times of need.
When we're talking about defense of someone's personal property 5 or 10 guy are an army vs a single man. And I'm not saying that the security that you hired would attempt to violate your rights (I would expect they wouldn't) but I'm asking the question of what happens when a large enough security group (or mercenary group if you will) arrives to kill or steal from you because someone else hired them to?
What do you think we do? We shoot the fuckers. It's not rocket science. Smart security/merc companies know this, and would charge exorbitant prices. The
really smart ones would refuse.
It's a legitimate question. Power corrupts and armies (historically) do enjoy pillaging. You simply can't rule out the chance that at some point in the whole thing some security providers would become predatory and/or immoral. Look at what some corporations already do to people.
Comparing today's corporations, hiding behind the regulations they paid for, to companies that would operate in an AnCap environment is like comparing a wolf to a dog. Sure, they're both canines, but one is a dangerous beast, and the other is tamed.