Workers who have been furloughed will only be paid back if Congress explicitly passes a bill to pay them. That has happened in previous shutdowns but it is not certain to happen this time.
For what it's worth, back pay is apparently part of the package in the Senate today. The House already passed legislation guaranteeing it, but for whatever reason (this article suggests Senate Republicans, but I don't know) it didn't get through the Senate.
They only get paid if Congress specifically includes language paying them. People are merely assuming congress will do so on what, good faith? Given the nature of this whole bruhaha, I wouldn't discount entirely the possibility of no back-pay.
The Senate didn't pass it. However, since both houses are passing the same thing but at different times or as part of different packages, it's all but certain that when the time comes back pay will happen.
There is no guarantee they will be paid! If they will, it will have to be specifically specified in the new budget. Why does everyone act like it is a given?
With a backlog of work to do once you return. Its not like an office or factory suspending operations because there is no work. Many of these people have deadlines that they won't be able to meet without a great deal of effort and likely overtime (if granted). So not only does this shutdown give them a "paid vacation" it's going to pay extra so that the work can still get done close to on time.
… and don't forget the politically charged atmosphere. You're still going to hear about how government agencies don't work but most of the attackers won't mention things like e.g. the way the VA was making progress on their backlog until October 1st:
