If you're only going to pick one thing that a government does, yeah, it's easy to cherrypick something awful. But the alternative is literal anarchy, which is a) much, much worse for the vast majority of people, and b) 100% guaranteed not to last, as the people either organically organize a government from the bottom up, or some violent strongman (gender-neutral) (but let's face it, probably a man in practice) emerges and enforces an authoritarian government from the top down. And in either of those cases, they'll levy taxes very soon, whether it's to make sure that the things that a representative government needs can happen, or just to take as much as they can from everyone else.
The purpose of a mob/mafia/organized crime group is to illegally enrich the people at the top in an organized fashion.
Some governments experience corruption that leads them to act similar to organized crime. It does not change the purpose of government, nor mean that it is inherently no better than the mob.
If you have a better suggestion for how society can be maintained, people can be supported, and the common defense ensured, that does not involve a government that is theoretically vulnerable to corruption, then by all means, propose it. You'd probably win a Nobel Prize.
But you won't, because there isn't such a thing. Once you're doing those things, you are a government. Any government, no matter how many or few people are involved, is at least theoretically vulnerable to corruption, but that vulnerability can be reduced by a variety of measures.
And saying "we just shouldn't do that" is a non-starter, both because it's morally repugnant and for the reasons I described in my previous post.
* The obvious exception here is authoritarian governments established by strongmen, as I described previously. However, I would posit that, over time, these will also transition toward seeking to provide at least some level of stability for the people under them, because the alternative is almost invariably to be overthrown when the people get sick of your shit.
ETA: ....But there are also circumstances where local organized crime is the closest a particular geographic area has to a government, and does, in fact, act the way you describe. In those circumstances, depending on the details, it could very well be moral to support the local mob.
