Argument from Personal Belief

The fallacy of argument from personal belief is better known as Argument from ignorance. I prefer to use AFPB to avoid drama over the word ignorant.

This is important, but I am lazy right now so I am just going to cut and paste from wikipedia.

Argument from ignorance, also known as argumentum ad ignorantiam or "appeal to ignorance", is a fallacy in informal logic. It asserts that a proposition is true because it has not been proven false (or vice versa). This represents a type of false dichotomy in that it excludes a third option, which is that there is insufficient investigation and therefore insufficient information to satisfactorily prove the proposition to be either true or false. Nor does it allow the admission that the choices may in fact not be two (true or false), but may be as many as four, (1) true, (2) false, (3) unknown between true or false, and (4) being unknowable (among the first three).^[1] In debates, appeals to ignorance are sometimes used to shift the burden of proof.
Argument from ignorance may be used as a rationalization by a person who realizes that he has no reason for holding the belief that he does.

 As this applies to ABDLs:

Someone might believe that ABDLs interests lie not in age regression and/or wearing diapers, but in real life children. This belief has no basis in reality. Just because someone believes something to be true does not make it true. And yes, this ties significantly into the shifting of the burden of proof.