No doubt you and some others didn't and don't like Rage. That's fairly irrelevent, as that happens to evey band. It is, however, highly doubtful that 2/3 of the crowd (800 people) walked out because they didn't like them. Never in the history of ProgPower USA has 2/3 of the crowd walked out on a band because they were unliked. Glenn doesn't sign bands that's likely to happen to, much less a headliner.
The fact is that few bothered to get to know them, because their back catalog was too much to bother with. The lack of familiarity resulted in the majority walking out because there was something they were more interested in going on outside.
That is in no way a reflection on the talent of Rage, regardless of whether they get played on your radio show or not. I would agree with Zod that if they only had 3 or 4 albums the familiarity, hence the attendance, would have been far higher.