Well it doesn’t particularly make sense but lots of policies around covid vaccines don’t make sense. I’m not convinced that making sense is really relevant.
I also wonder if I’m missing something here because as far as I’m aware the cost of getting a booster is feeling a bit rubbish for 0-2 days. Is it not normal for universities in the US to require (non-covid) vaccinations? I know my university required a bunch when I went up.