It helps to know the origin story of the "create money out of thin air" line.

In past decades, some fiat currencies were gold backed. It means paper bills could be exchanged for gold.

Later some mints abandoned this practice. Critics accused mints of "creating money out of thin air". Printed paper money was no longer backed by gold, precious metals, oil reserves or anything of intrinsic value.

This is a criticism that has been made about the US dollar for decades, since it abandoned a gold standard in 1933.

That's the origins story of "creating money out of thin air".

Some now use it to criticize crypto. In most cases, it is a poor criticism. Due to tether and other crypto being better backed than most assets in the world.