I didn't mean to derail the thread, should maybe have started a new one dedicated to this. But somehow I feel it is tangentially related to the "mess" in Amsterdam, given these people are a "mess" that the world would not miss. The KLM lounge lady at the entrance to the lounge told me that they are employed by Schiphol airport, are constantly on a power trip, so just stay cool and ignore them. Good advice. Don't like being shouted at, though.
On a previous trip, to Birmingham in June I think, I saw them being verbally abusive of a passenger with limited English, really saying stupid and unacceptable things. I wanted to intervene, but it does not pay to interfere in other people's problems. I would like something to be done about this, though.