Hmm...I mean Junior did have his own song where we talked about catching and kicking the Fraggles. But I think I agree that for the theme song, it needed to be a bit more ambiguous so they didn't appear like out and out bad guys.
I think people can have their own interpretations (that's what fanfics are for, hehe), but I personally don't think the Gorgs ate the Fraggles. Pa and Ma seem more disgusted by them than anything, like they're rodents. And they don't act disapointed when Junior fails to catch them, like they're missing a meal. They're more annoyed that Junior's going through all the trouble.