All residential in US has 240V but split in 2 phases. This is true even for apartment buildings. Most of the stoves and driers run on 240V, so please .. almost everyone in North America has a 240V service.
As for the disclosed hashrate, they disclosed one, together with the conditions to get it. It's not their fault you live where you live or you host it where you find some decent rackspace without asking about the power requirements.
True. And installing another 240v line isn't as expensive as you might think. The bigger concern is really space and cooling ... and security if you get that far.