the linked article did mention apartments were "abandoned", so maybe it is actual organized crime local to NYC. Whoever it was would have to be pretty entrenched to know where is safe to set up.

If it were just run of the mill spam/scam stuff, why not just use VoIP or contract out like the rest of them do? It would certainly be cheaper if that were the goal. There are many, many different reasons to want so many local numbers that are beyond the obvious. Personally, I have questions.

Or they’d keep their DDoS device in their embassy and do it from there.

If such activities are in any way traceable, it might be prudent to preserve deniability by siting them somewhere other than the embassy.

But having said that, this looks much more like an SMS bot farm, designed for smam'nscam purposes, that caught the Secret Service's attention because it was being used by someone to obfuscate the origin of threats.

If the treasonous idiots in the Trump administration hadn't fired most of the governments cyber-security experts, we might have seen a less hyperbolic, hysterical analysis than what the Secret Squirrel Service has published.

But as things stand, it's a bad idea to believe anything the government says, since it is being run by people who are neither competent nor truthful.