1) essentials, who are required to work and will indeed likely be repaid
2) non-essentials, who are not allowed to work and will not be repaid. They've effectively been forced into an unplanned month-long+ leave of absence. To be honest I feel worse for this group, though it sucks for everyone.
ETA: this is inaccurate, was thinking of contractors. Though I do wonder how hourly workers will be handled.
Which is to say we'll have forced some people to work for no pay, and paid others for doing no work. (Yes, the pay is in fact just delayed. But "no pay" is pithier.)
But maybe I'm wrong, the article is actually quite unclear.
On the flip side, different contracting agencies handle things differently. Some will let you take Leave and go in the hole while others will subsidies the shutdown for you.
As always it's complicated, but it's a good assumption that someone in the contracting chain is losing money.