The top reply addresses your points:
> The hacker spirit is the fun of reverse engineering. The hacker spirit is about personal use.
> It's not expecting to be able to turn it into a business, or a popular app, that wouldn't quickly be shut down. That's just common sense.
Beeper’s CEO is acting high and mighty, speaking like he’s some kind of ideological liberator, while charging for a service using another’s infrastructure. Had it been free and open-source from the start¹ you’d see a lot more people on their side. As soon as you start charging, you lose a lot of “hacker” sympathy.
It’s possible to disagree with Apple for not providing iMessage on Android while at the same time disagreeing with Beeper’s approach.
¹ And I do mean the whole app, not the proof-of-concept from the teenager.