Imagine you are a Roman and arguing that slave owning is necessary to a functioning society. You are probably even correct and Roman state wouldn't be possible without slaves. Nevertheless, we know that it wasn't an ethical state order. Taxes are similar - they are involuntary, they are required to have a modern state and they are status quo.

Looking at the past, we see that more and more ways to force people do things against their will were discovered as unethical - e.g. slavery, feudalism, divine rights of kings, coverture.

I think there is a non-zero chance, that future people will consider modern taxation (and probably the idea of Westphalian sovereignty) unethical too.