Originally Posted by Rainard Jalen

the problem is, they shoulda just called themselves the pixies in the first place if that was their intent. intentionally omitting to have the "the", and it must have been intentional and with some particular reason in mind (because it is against what is conventionally done with plural noun band names), suggests that they wanted it to be called just that: "pixies", with a "the".

they probably shifted in their own referential use over time when it turned out that everybody else called them "THE pixies".