not even the supreme court can define obscenity https://en.wikipedia.org/wiki/I_know_it_when_I_see_it
It doesn't bother you that a sizable proportion of mostly harmless messages on Facebook, Twitter, 4chan, etc are suddenly potential felonies? And that they can be used to target innocent individuals by the federal government?
What happens when a legitimate whistleblower becomes a problem, and suddenly an angry twitter rant becomes an excuse for arrest?
I don't see that. The GP accepted your statement, that it requires intent to harass and abuse, and commented on it.
Also, why should the GP accept your analysis? Do you have expertise?
In case it isn't obvious, I'm not a lawyer. No one should accept my analysis, because I'm a stranger on the internet, or a Turing-Test-succeeding imitation of one. Likewise, I'm not going to accept OP's analysis for the same reasons. But I will participate in a discussion that allows readers to explore alternate ideas and viewpoints, chasing an overly-idealistic goal of inspiring each of us into self-driven personal growth. Because that's a virtue worth striving for no matter which side of the argument you are on.
Edit: The other provision requires the sender of obscenity to know the recipient is under 18 - this is worth re-evaluating in the light of two consensual teenagers, but is nowhere near the sky-is-falling everyone-goes-to-prison since it's hard to prove you know recipients of an anonymous message board.