Yeah, but perceiving functions are still an intepretation and biased orientation to reality, even Se and Si.
Yeah, it does process sensory data first. All the functions filter incoming data through our senses, it's how we live, of course.
I think you think, that sensing functions are just are just raw reality and that they are an accurate view of actual incoming data. They aren't. Se and Si are still perspectives and abstractions of actual reality just Ni and Ne- all the functions are and none of them, technically, are objective.