Why does the US have to borrow the money it prints?

 The question is obviously absurd. The government isn't a household, and debt isn't a "burden" if you can print the means to repay it. Yet the propaganda saying debt is a big problem is absolutely relentless, and well-funded.

Yet, while poor people want good governance, rich people want no governance. This is why we continue to elect the expensively, and extensively-marketed dotards and dementia patients, and pursue policies that are self-sabotage.

There's no better example of the kind of dementia-induced word salad answer to the title question than this interview with an administration's economic advisor. Jared Bernstein was the chair of the president's economic advisory panel during the Biden administration.

 On the right, the attached graphic shows that the private sector surplus is a mirror image of public sector debt. Reducing the public debt sucks money out of the economy...with predictable results, i.e., a wave of asset forfeitures and foreclosures--just the kind of thing vulture capitalists relish.

Historically, 100% of the time significant national debt reductions have occurred an economic downturn follows. The Coolidge and Hoover administrations diligently reduced federal debt...and the Great Depression followed. Andrew Jackson paid the national debt off (and closed the central bank) in 1835. No public currency!

Yes, dollars say they're "notes"--IOUs--and are part of the national debt. After Jackson paid off the debt, people did their business with monetized gold ("specie") and over 7,000 varieties of private banknotes. The "Panic of 1837" followed.

Note that the left side of the graphic above shows private debt peaks precede economic downturns. Not a surprise, since public debt mirrors private surplus, and those debt reductions reduce private surpluses.