A sovereign act of pardon and oblivion for past acts, granted by a government to all persons (or to certain persons) who have been guilty of crime or delict, generally political offenses
I think an amnesty is only a pardon of past crimes. And there are criminal and civil penalties for illegal entry into the US and illegal presence.
How do these politicians leap from a pardon for past crimes to legalizing the status of illegal entrants and allowing them to stay? It would seem the proper actions after the amnesty would be to say, we aren't going to prosecute you, but now we must begin removal procedures.
And there are penalties for illegal entry and illegal presence in the US.
McCain said that the McCain-Kennedy bill was not amnesty because the lawbreakers had to pay a fine, learn English, and get to the back of the line. Ryan said the Gang of 8 bill was not amnesty using the same reasons. It is just the parsing of words to fool and deceive.