Very good question! Funnily enough, it was indeed a conscious decision to avoid mentioning "inference", because then people might expect that we're doing polymorphism with type variables/or maybe that we're deriving a Hindley-Milner inference system.
We're not doing these things, so we figured it would be safer this way, but absolutely you could call what we're doing "type inference".
That being said, we've got some ideas for a follow-up paper to revisit this and derive something more worthy of being called "inference".