Not to mention their servers were located in a US datacenter, which means they can quite easily demand to seize the hardware. Not the brightest idea to host it there to be honest.
Which US datacenter where the servers located in?
They were hosted by Cloudflare which is a US company. Exactly where the servers where physically located I'm not sure, I think I read somewhere in the US. But either way, as Cloudflare is a US based company the FBI can demand pretty much anything from them under US law and they have to comply, even if the servers were physically located abroad (which I don't think they were, I think it was a data center in california).
they weren't hosted by cloudflare. that was just for DDOS protection services. they have nothing to do with the exchange's datacenter. i don't think it's public information where the seized servers were. and the seized servers may have just been running scripts to yet another remote server. we really don't have enough information to opine one way or the other on how intelligently they set up their infrastructure.