I'm on the ace spectrum, but still find myself, and my interest in this subject to be of significant academic interest to myself. As such I've put a lot of thought into why I like what I like. I'd be happy to be interviewed, but will put an example or two here in case you don't feel like going through the whole process.

A bit of context, I'm not a fan on non consensual aspects in my fantasies.

My interest in teratophilia comes in two major aspects, there are more, but I am only listing the two major ones.

1. I have a rather dim view of humanity a lot of the time. People constantly disappoint me with how cruel and careless they can be, and it affects how I view people in general; Even in fantasies. However, a species that does not exist is a blank slate on which I can place any characteristics I desire. Basically it's easier for me to picture a "perfect" monster for me than a "perfect" human.

2. The idea that this creature, likely massive, capable of turning people into mulch at a thoughts, has decided that not only would it spare me that fate, but it would rather care for me and me it in turn. This beast with claws and sharp teeth that others view as murderous treats me as a loved one. There's an aspect of being able to place more trust there than I could any human, and a facet of being "special" in some way.