Why is a private business inherently better than the government as an ISP, though?

Either way it has to follow all relevant local laws about how to behave. The ISPs will respond to law enforcement requests either way. But at least a public entity will also need to be accountable to the public and respond to things like FOIA, as opposed to a private entity which has all kinds of ways to resist transparency and is more accountable to the shareholders.

Either way it is a near natural monopoly because running redundant wires/fiber is a waste of resources. There won't be much consumer choice.

The idea that the government would be inherently inefficient is one that presumes a private entity that is highly insulated from market force wouldn't. Free markets create a lot of pressure to improve products, but there's no free market happening in a utility like an ISP. Even in the most competitive markets, that's still choosing one from maybe 4 providers that barely compete with each other at all. And you have to sign longterm contracts with all kinds of complex pricing to "test" the competition, and testing it requires pretty advanced knowledge beyond most users -- if you have no freedom to easily change your ISP, there's just not any competition.

If the sword is double-edged, one of those edges is safe enough for a renfair.