I'm surprised students put up with it, but they don't know anything different. They hear about US students who argue every single grade but I don't think they realise such students actually exist.

However I'm really happy to be away from my first (US) academic post where I constantly faced pressure from an athletic department to "relax" on grades or overlook "minor problems" from athlete-students. Post exam argumentation from individual students is easy enough to deal with reasonably and honestly, institutional forces are another beast entirely.