> Whereas in the US you only need to go through fingerprinting only once
Once for each arrival.
No. I haven't had to do it in at least two years and I travel here frequently on an EU passport.
not for US citizens at least, whereas I get fingerprinted entering and exiting as an EU citizen in the EU.
Not my experience the last time I entered. I travelled with a friend for whom it was his first time visiting the US. He was fingerprinted, I wasn’t (I was fingerprinted a while ago on one of my previous trips.)