I don't think the guest worker program equates to "amnesty" - though I'll be the first to admit it's wide open to interpretation. My interpretation, though, is that "amnesty" is a global, no-questions-asked, forgiveness of any legal violations...basically equivalent to an umbrella presidential pardon. The work program, on the other hand, is more of a quid pro quo situation: you do for us, we'll do for you. Pay your taxes and fines, put in your time, and we'll give you citizenship. In effect, it reduces the penalty for illegally crossing the border to a stiff fine while increasing the tax and SS base...
...which, when you think about it, is a pretty smart idea all around. Of course, this administration has a long demonstrable history of taking smart ideas and implementing them atrociously...but it's still a pretty smart idea.