My quote comes from the song "Frazzle." I always thought Frazzle was a neat looking Muppet because he doesn't have that typical cuddly, cute appearance. Apparently, Frazzle seemed to scare kids, so he wasn't used much on SS. In fact, he was pretty much an anything Muppet, & was not even an official puppet until the later years of the show. With songs like "Fuzzy And Blue" (And Orange) Frazzle kind of got a little more exposure, thus The Frazzletones performed on the song "Frazzle" in what I would guess is a way to show that Frazzle may look scary, but he's really nothing to be afraid of. They describe him to have feelings & be an overall cool guy. The Frazzletones are kinda just background muppets for the song, to add contrast.
(Frazzle really never spoke, other than grumbling, but I have the faintest memory where I could swear he may have actually spoke.)