The company that issues tether can invest the proceeds into a money market and get some meager interest. If that float is large enough, they can make a killing in absolute terms. Presumably that's what the grandparent means.
The company that issues Tether can issue it without receiving any USD. If that issuance is large enough, they can make a killing in absolute terms.
notably tether doesn’t guarantee the right to redeem the tokens for dollars, so they can do whatever they want
Interestingly, Tether has "broken the buck" before, trading below (or sometimes above) $1 parity.