Sure there's this principle but this just moves the need for justification. Humans leave their traces everywhere so why this principle for mountains? There are many traces that should be removed such as hydroelectric power stations, river straightening and so on. Is this whataboutism? I just think a few bolts in a mountain don't do much harm and as a casual observer of these mountains you won't even notice. Also I am very much for "leaving no traces" in the sense that everyone picks up their trash.

> Humans leave their traces everywhere so why this principle for mountains?

It’s called conservation. It is why we have these places to climb in the first place. These are protected wild places.