Earlier quoted context omitted.
You appear to be assuming that the entire team of people at twitter who work on these problems either haven't considered or aren't able to address these issues. While there often are challenges with moderation and rules enforcement, this kind of stuff is pretty easy to address.
Given that I have wrestled with 2) in a different context, I'm quite interested in hearing the various (hopefully realistic) methods to address it. Actually serious.
But if you look at that profile, he says he works at Google. Think about that for a second. He claims this is an easy problem. But consider Google's approach to spam detection algorithms and see how there are so many false positives and innocent people getting screwed out of their ad accounts and livelihood. If this kind of stuff was easy, why hasn't anybody informed Google about it?
I'm not trying to pick on anybody here, but I believe there's a level of arrogance in thinking that this form of sabotage is somehow a solvable problem unless you somehow have access to all communications on the planet.