>>25259288Not just humiliation, but it also has underlying de-humanized fetish tendancies. Not unlike a gag, which is designed to stiffle speach and thus takes away from the wearer something they had since they could remember, the lack of the ability to talk and communicate with words is something that makes us human and taking that away can be detrimental to some. Also, depending on the gag, taking away the ability to hold back saliva and forcing the wearer to drool without their control oe consent adds to this de-humanization aspect, because humans have the ability to not do that and drilling I'd looked down upon or outright mocked when it is witnessed happening.
But enough about gags. The point was that it can de-humanize the wearer like age play and diaper can do. It takes away something the person has strived all their adult lives to work for in their bathroom usage, and by taking that away the person feels les of a human. Age play is also used by Dominants who want to control their sub but don't want a very strict type of Master/slave dynamic but instead a caregiver you're relationship, which in many regards is similar. And there are subdivisions of what each person would like to do. Not everyone who partakes in age play wants to wear a diaper, just like not everyone who wears a diaper might want to use it. It is complicated and there is no black or white answer or guide for this.
In the end there are as many countless reasons why someone has a particular fetish as there are fetishes themselves and to each their own.
I hope that made sense, I'm suffering from insomnia and writing from my phone.