The root of this problem, I think, is that Apple requires the $100 membership fee (and thus provide a developer account) even for testing apps on one's own device. If Apple, instead required this fee (and gave developer accounts) only when somebody has submitted an app for publishing on the App store for the first time, then there would be a legitimate filter against people who like to download betas just for experimenting or are plain nincompoops pretending to be tech bloggers.
As an added benefit, by doing this, Apple would also invite a LOT more developers into its fold who would like to experiment with apps on their own device without committing to publishing any.
If iOS7 serves as an example, this would be a terrible idea. Betas 1/2 were nowhere near acceptable for day-to-day usage, and while the new betas are better, I still get app crashes and even phone restarts every once in a while. Letting everybody use the beta from the very beginning would be the far worse thing they could do: all of a sudden, with no notice, every developer out there would be forced to fix crashes asap to avoid millions of people complaining about it. And it would pretty quickly cause people to hate apple's phones, because they "crash all the time."
The GP wants to limit the betas to what I will refer to as actual developers, measured by those who have submitted an app, so you both want it to be more restricted than it is.
As an added benefit, by doing this, Apple would also invite a LOT more developers into its fold who would like to experiment with apps on their own device without committing to publishing any.