Wow, people really hate glue ons.
Prior to his quasi retirement (and move across the country) I used a farrier (Dave) who just loved glue ons. And honestly, his were kind of amazing. They were not like the sigafoos, with a cuff. He would trim the horse, shape the shoe, and then mix a little container of epoxy-type stuff and use it to set the shoe pretty close to how you’d use nails to set the shoe. Very little glue used and traditional aluminum shoes (or whatever else you wanted. I showed hunters with that horse and used aluminum)
Prior to using him I had from time to time had glue ons from other places (including a couple of times the farrier at New Bolton) and those glue ons SUCKED. The glue ons Dave did were done in a totally different way and they were amazing. Those babies were NOT coming off. And they did help my horse with kind of thin soles and fragile feet finally grow out some decent hoof. In the 6-7 years I used Dave to shoe that horse I think my horse lost one shoe, and it was at a show when he stumbled, almost fell, and literally stepped on himself scrambling to keep on his feet.
Unless you begged him otherwise, Dave would do your horse in glue. It was just his preference. And he charged the same for glue ons or nail ons. So there wasn’t a price difference.
He was a pretty in demand farrier for high profile folks, including horses that rode for the American teams.
So I don’t think it’s ALWAYS a bad sign that a horse is in glue ons.
Now, if you don’t want to deal with glue ons, I get that. No glue ons that I have ever seen other than Dave’s were anything I would EVER want to deal with. But it’s not automatically a sign that something is wrong when horses are in glue ons. There are some farriers that just prefer to shoe that way and do it well.