Only if you abandon any definition or replace the existing one with one of your own - I do neither.

All I'm doing is reporting on what I've see around the UK Folk Scene for the last 35 years, which leads me to say that:

A Folk Song can be any song sung in a designated Folk Context. At other times, and in other contexts, the same song might be something else entirely, a Pop Song for example, or yet a Jazz Standard, a Victorian Parlour Ballad, a Musical Hall Song or even an Operatic Aria. All of these I have heard sung in Folk Contexts and have, by dint of that context, accepted them as being Folk Songs. So what makes it a Folk Song is the context in which it is being sung and appreciated as such.

As for what makes a Traditional Song, the lines are clearer with respect of a canon of material collected, recorded, catalogued, cut and dried, sourced and analysed, numbered, indexed, with occasions, performers and variations duly noted. Sometimes Traditional Songs might be sung as Folk Songs, other times they might be sung as Classical Songs, Rock Songs, Wyrd-Folk Songs, Jazz Songs, or Pop Songs. Anything is possible with a Traditional Song - but the song, essentially, remains the same, whatever the context.