Is there a sudden epidemic of such behaviour from ground staff, or is it just that contributors are only now relating such tales?
I had an identical experience with KLM at Schiphol just two weeks ago. At the end of a long, slow-moving bag drop line, a KLM representative removed the barrier and invited half a dozen of us to move to the business class desk. The business class check-in clerk was not happy and demanded that I return to the economy line. She continued to be grumpy and dismissive even after her colleague had confirmed that she had invited us to move to that desk. She even told me that next time I must remain in the correct line even if instructed otherwise. Before heading through security I filed a complaint with KLM customer services.
But I'm not going to judge an entire airline by a single incident or by the behaviour of a single member of staff. And if I were, which member of staff should I choose to represent the airline - the one who kindly tried to reduce the time we had to wait, or the one who was unhappy that we had done so? I will continue to fly with KLM - who, in my experience, are second only to BA in the quality and consistency of their product.