20% of federal expenditures are for defense. The oft-sited 50% is discretionary budget, which doesn't include things such as social security, welfare, etc.

Nonsense. The basis of "civilization" is the just rule of law, and protection from external threats. Which are paid for by your taxes. Without these things, it would be impossible to create technology startups.

Most folks who complain about taxes aren't objecting to the very existence of taxes, merely the fact that they're excessive, largely spent on things that they shouldn't be, and disproportionately lumped upon a small sector of the population. Few would complain about, say, a flat 10% tax rate to support basic infrastructure, courts, police, et cetera.

On the other hand, there are folks who genuinely believe that taxes should be zero. They're welcome to move to Somalia.