I don't think it is an environmental nightmare. I think it is part of an environmental solution, if used properly. Some of that gear should be mechanically separated first, but once certain parts have been removed for separate processing, a lot of gear can be turned into more manageable material for recycling, and some things can be separated out in later stages using various magnets and filters, temperature, etc... in a flow process, which might be efficient and effective if set up right. For example, empty plastic cases can be shredded into a more workable size of particle before being further processed for re-use in some other format. Tires can be shredded with that machine for recombination and re-use as playground cushions or road surfaces, etc... The shredder has its use as part of an environmentally-friendly solution to the problem of excessive waste.
But NOT used as they are showing there.
That was interesting to watch, in the way an automobile accident can be interesting to watch... but equally unsettling, as well.
I also shudder to think about the fine, restorable vintage audio gear and televisions and other types of historical technology that might be destroyed by that thing, and the rate at which it can eat up such things is frightening to contemplate.
Judgement and wisdom should be applied to the CORRECT and suitable use of such "technology". Just as a knife that can be used to carve a work of art can also be mis-used to kill a child, this tool by itself is intrinsically neither good nor bad. It becomes good or bad, according to how it is used by the people controlling it.