Very cut and dry CFAA case, I'm guessing Beeper saw how well it went for Epic Games when they leveraged the useful idiots to sway public opinion, so they are doing the same for a quick buck and hoping it gets political enough to avoid getting fined.
But we shouldn't have to get to such specific examples to discuss the issue at play here—Apple is fighting against adversarial interoperability. I'm amazed to see people arguing in their favor on Hacker News.
Does that mean they are therefore not competing with Apple? And if their users are using Beeper Mini to access iMessage, are they not implicitly accepting the ToS?
Courts generally do not find that ToS can be accepted implicitly, even in situations where they are actually shown to the user: https://en.wikipedia.org/wiki/Browsewrap#Case_law