This assumes that whoever set these up made sure there is no interference and hikes up there to remove the device when it breaks instead of just leaving it up there to rot.

It would seem that hogging up spectrum so you can surf the internet is probably a selfish usage? I mean most ham operators don't go 24/7 while talking and using channels.

Bandwidth is a finite resource. An installation that is open for everyone to use still harms other people who would like to use that bandwidth for other purposes.

That's assuming any traffic is being sent. Installing the hardware doesn't automatically cause any harm.

Installing hardware that isn't doing anything is just littering.

I didn't say they were harming anyone. They might be. Frankly I have no idea.