This seems to be ignoring consent. I'd bet you if I went around asking people whether or not they realized their FB app experience was being consistently multivariate tested i'd be on the street a while before someone said yes.

This is FAR different from product testing, say in the hardware world, where you tell people you want them to come test a product, or in the design world where you show them various things and quiz them on their feelings. In these situations they all know they're being tested on.

So no, this isn't "the least" user hostile thing you can do. Doing things without content is basically the prerequisite for hostility here.