You wouldn’t go to Thailand or Egypt or Brazil without educating yourself around what’s considered good or poor manners when you dine out, or whether it’s rude or an expected norm to offer a tip, or how to make sure you don’t offend locals by behaving inappropriately, or ensuring you don’t embarrass yourself by failing to acknowledge local customs. So why would you go to the US and let yourself find something jarring / be taken by surprise that service is an additional charge in hospitality? You can find this information out in any travel guide.
The US is a completely separate country. I think the crux of it is that some British people seem to think of the US as still some kind of offshoot colony of the UK which should be exactly like the UK (hence the indignance of some Brits at American English being “wrong”, and US customs around festivities which are deemed “tacky” or “showing off”) and that things in the US will be just like at home, but bigger, and in a different accent.
You're putting words into my mouth there. This thread is about how strange the American culture seems to Brits. Virtually nobody is saying that they wouldn't comply, nor that they're surprised THAT it happens, just surprised WHY it is the preferred way.
I'm not anti-American, nor saying that American = wrong. I've been vocal before on previous threads about tipping in the UK, which I am also not a fan of - not because I am 'tight' as some people like to emotionally couch it, but because I think wages shouldn't rely on charity and goodwill on the part of one party in the transaction only, but should be part of the stated/agreed price.
We are allowed to voice an opinion on customs in other countries that seem strange or objectionable to us, though - just as people in other countries are allowed to discuss British customs that they find strange or objectionable.