If it were a show where the expectation was you wouldn't be filmed getting in and out of the shower, etc. maybe I'd feel differently.

I mean once you agree to camera's in the bathroom you've pretty much said you will do anything on camera. I do not know that they were told as to what to expect in the way of what they will be asked to do in competitions (given the show's theme is expect the unexpected I'm pretty sure they are told to expect anything and everything and had a chance to back out if they weren't willing, they didn't force them off the street and into the house). Even if you know there is an outside chance you might be asked to strip all your clothes off it can still be a bit of a shock when you find out now is the moment. Most of those who seemed most uncomfortable at first sure did seem to be fine with it as the competition when on.

I'm not sure why this nekkid competition is somehow more degrading or coersive than pouring disguting stuff on your head every hour for 24 hours or any of the other things that no person in their right mind would do on camera or off.

Was it gratuitous, absolutely. But so is pretty much everything else on the show.