I wonder if I would like to challenge that conviction, and see what you think. The reason I would like to do this is that until a month agao, I kinda settled with the explanation that I was much better at taking care of the tanks with Hypancistus's in it (Zebra's and L260 - not in same tanks), but a recent happening has made me wonder if they actually - intentionally or not - eat the stuff.
Consider this:

This cave came from one of my other tanks, that unfortunately does have an algae problem - not too much, but enough to be annoying. I put it in the Zeb-tank during a refurbishing, and it was much heavier infested when I did this than it is on the picture. I'm not going to insist on this though, as I don't have a picture of it, this was taken some time later. See the algae around the edges of the cave?
Now, a month or so later, it looks like this:

Squeaky clean.
I have three tanks with Hypancistus's. None of them have these hairy algae. I wonder if they inadvertently gnaw them off while actually looking for microorganisms living amongst the algae? Getting their veggies even though they don't want them

What do you think..? I'm absolutely open to this being pure imagination, but it sure has made me wonder!