Most of this stuff appears staged. Seems to me it destroys the entire rationale behind glory holes when people are simply standing either side of a partition and able to peer around to see who's on the other side. The real thing, surely, is when the glory hole is between two cubicles, each with a locked door, and the excitement comes from sitting on the toilet seat and waiting for what might come through the hole next (or who might come along next and invite YOU to slip through the hole). A bit like a lucky dip, really. Might not sound like safe sex but then you don't HAVE to participate fully if you don't want to. If a particularly nice cock appears you don't have to suck it - an admiring fondle or a jack-off will do. And if you're apprehensive about putting your dick trough a hole - maybe the person on the other side has a chain-saw or scalpel at the ready! - then don't do it.
I have fucked and been fucked via a glory hole and I have sucked and been sucked via the same route. Sad thing is that there are so few glory holes to be found nowadays, and, when you do find one, its life is relatively brief because the local authorities soon "fix" it - usually with metal - and the search begins again for another.
The key aspects of glory holes are excitement, danger and anonymity.
This turns many people on. A lot of straight guys are happy to be sucked or jacked off when they don't have to actually face someone or look him in the eye. Many are also happy to put on a jerk-off display while you watch through the hole. I have seen some spectacular equipment this way over the years - far more visceral than watching a porn video or flicking through a mag.