It shouldn’t be allowed at all. They’re giving republicans lots of ammo, if they’re smart enough to use it.
The GOP could care less. 70 Senators allowed FATCA to become law in 2010. The RNC "called" for a repeal in 2014. Of course that was "safe" to do as it had zero chance in the Senate. After that, crickets.
All Biden and Co want, is for FATCA to apply to everyone, not just the ex-pats.