Ok....this is MY understanding of how this terminology is typically used in the ball python morph world.
The term "het albino" is just a shortened version of "heterozygous for albino".
Therefore, the term "het lesser" would have the same connotation, "heterozygous for lesser".
And given the utter confusion on the matter, no matter which side of the argument a person is on, why should "het" be used in reference to lessers (and other dom/co-dom morphs) in the first place? Applying the term "het" in such a redundant fashion IS confusing. You don't call an albino a "super albino" or a "homo albino". It's just an albino.