As someone in the UK and used to dealing with UK-based recruitment agencies, I didn't understand the recruiter hate until I had my first experience with one of those shitty "agencies" that claims to be in the UK (or whatever they're targeting) but is actually ran from a third-world call center right next to the tech support scammers. When it comes to those, obviously all bets are off when it comes to your personal information, and the recruitment industry in the US seems to be saturated with this scum much more so than in the EU.

However, even legitimate recruiters can be a problem if you get too many of them. I recently had to rotate my business number because I was getting pretty much one call a day from someone wanting to "have a chat". They're all nice, courteous and seem to know what they're doing, but the sheer quantity became a major problem especially when you're already fully booked and aren't open to new business.