At airports that do this I find it’s more common when US TSA adopts a rule first that people don’t want to subject all air passengers to. It was really common to have gate lines back when the US introduced that 3 oz bottle max.

The situation at AMS is that they kowtowed to the American government. The extra security doesn't apply to anyone flying a non-American airline (e.g. KLM) just Americans on American airlines flying to America. Used to be you'd have to go wander to a secondary screening station but when I flew through in 2019 they just pulled you out of line at the gate. I've not seen another airport that does this (in Europe or elsewhere).