“Who’s FICA? And why are they taking my money?”

Actually, he asks about the income tax in general, given that almost 50% of Americans don’t pay income tax.

This is not a bug; this is a feature.

The income tax is a specifically progressive structure. It exists to do two things:

1. Feed the Beast
2. Give the Federal Government a permanent managerial role over the economy and the structure of society.

Or, as Bill Quick puts it:

It’s a great idea if you’re a statist who wants government to grow big enough to control every aspect of its citizens’ lives.

And people keep ignoring this, because, egalitarianism.