The bidline argument is a reaction to pressure from pilots that we, as cabin crew, must change our T&Cs.
For what it is worth I believe it is an unnecessary and unwelcome distraction that plays no part in my departments negotiations. However I cannot tell you how many, otherwise friendly pilots, have placed pressure on cabin crew, critisied cabin crew, and delivered un-prompted lectures to cabin crew. There is bound to be some form of backlash. It doesn't help and I've ignored it, but it's to be expected. The term, it runs both ways, could be considered.