Because the externalities are not always visible, and people do not have enough free bandwidth to spend the time understanding them.
> If you get hand wavy and tell me its too complicated [...]
Unfortunately, it really is too complicated. A doctorate in economics might get you a decent way towards understanding the good that taxation provides, but given that economists still have differences of opinion, maybe not a complete understanding.
[^0]: Well it is, but only a tiny proportion.
Unlikely. Economics doesn't even understand how the monetary system works, let alone taxation.
Taxation works more like memory garbage collection than anything else. It's a cleaning up process.
It isn't an inherent good. It's just required to reduce demand and release people so the public sector can purchase them with its money.
Without it you would have inflation - or none of the public services we voted for.
The reason you pay tax is that your income is higher than it otherwise would have been without the government spending.
What people who don't like tax forget is that should you eliminate it, the increased income will be eliminated too. But not in a smooth way. Jobs will be decimated, and one of those might be yours.
If taxation is such an inherent good then why does it need to be hidden from people?
If the rate is justifiable the government shouldn't need to hide it. When you consider a democratic society where the government at least indirectly serves the will of the people the idea of the government needing to pull a fast one on the people or obfuscate its actions lest the people tell them to stop becomes even more absurd.