What the President is authorizing is amnesty, insofar as "amnesty" is defined as the overlooking or outright pardon of past offenses. He is, after all, shielding certain people from legal action. What's critical in this specific example, though, is that President Obama's "amnesty" is temporary and revocable.
So I'm actually giving the right wing media a pass on the use of the word "amnesty" in general, since it's technically correct. HOWEVER, the spirit of their use and the way it immediately dovetails into misinformation is...troubling (to put it mildly).
Using juxtaposition and bloviating, they have successfully created the illusion that "amnesty" = citizenship. They can't, of course, outright accuse the President of offering citizenship to the people he's looking to protect; he's not doing that because he can't legally do that. But they don't mind creating that impression among their viewers by dropping the word "amnesty" and then immediately talking about immigrants' use of social services, voting history, enrollment in schools, etc.
This gives the impression that amnesty = citizenship. There are millions of Americans that sincerely believe President Obama yesterday just made 4 million previously undocumented immigrants U.S. citizens. They base much of their rage on that fact (and Obama's skin color). So the technical correctness of the right wing's use of "amnesty," combined with their deliberate efforts to "enhance" the meaning of that word, has worked like a charm.