Why is the glory hole so very attractive to me? It's a hole in the wall. It might be in a public bathroom at a gas station, or in the bathroom of an adult theater (my first experience was there). There are many at adult video stores in the viewing booths. Some people set them up at their house and they advertised on the now defunct Craigslist. They all seem to attract certain people. Part of the attraction might be the anonymity, and for some the attraction is the chance of being caught, or the thought that others will see you. If you want anonymity certain venues are ruled out. Sometimes the drive to have someone tease the semen out of your cock, or you sucking the semen out of a cock, overrides some of the fear of being caught, but there are people who find the glory hole attractive and sometimes irresistible, whether it is to have your dick sucked or to suck and worship an anonymous cock.
The hole in a public restroom, whether it's a gas station, or an adult theater, or a public park are usually somewhat small and rough cut as though they were done a little at a time until one day there is an opening large enough to fit a cock through. Over time it might be enlarged and the edges smoothed, but until then, a cock that could fit through before it is erect is too large to remove after it has been licked and caressed by lips, tongue, and a gagging throat and it's fully engorged. That can be embarrassing or part of the thrill. Imagine having your dick caught in a hole when someone walks into the bathroom, or if you're in the stall without a door and a huge cock is caught in the hole in the wall. The graphics on the wall made by some folk artist add to the atmosphere and there are stains running down from the hole that are from cum and saliva. All of this becomes part of the sexual attraction. The imagination pictures the different scenes of someone's head close to the wall with a cock pumping through the hole making saliva spew out, or a cock that pulls out just before the cum shoots out. The man wants to see his semen shooting out and it squirts through the hole and some hits the edge and runs down the wall. All of these markings show how someone's frustration shot out in a joyful moment.
Video booths at an adult store are sometimes intentionally cut and taped or smoothed to purpose, while some have no holes in the walls or doors on the booth. To suck someone's cock you have to do a little flirting dance to understand the locale. If there are a lot of regulars there, they know the game and recognize the players, but if you are unfamiliar with the locale, you must find out with your little dance before you feel free enough to pull out your cock or get down on your knees and start choking on a stranger's cock with other strangers walking by and looking in. Some locales are so open that everyone who enters has the intention of some kind of sexual encounter without fear of repercussions.
Some places have booths for privacy with professionally cut and trimmed holes, along with larger viewing rooms, and a larger theater with general seating and a large screen. You might freely pull your cock out at any time the masturbate or tempt someone to start sucking on your cock, or you drop to your knees in front of some seated patron who is playing with his cock. Some of these theaters have couples attending regularly so the possibility of a bisexual encounter is good. A female might want to see her male companion getting his dick sucked or on his knees with a dick in his mouth. Or She might be there to for her own personal encounter to have her tits fondled or her pussy licked in front of others. Or they might choose a more private room for more intense encounters, but that is usually saved for private swingers clubs.