"but the number of Hispanics who takes the Aztlan nonsense seriously is near zero."
I take it you haven't been to a university campus recently.
Actually I have. Students adopt a lot of stupid and superficial causes/slogans, which they soon don't give a damn about after they start working 40+ hours, paying a mortgage, and feeding a child.
College kids believe a lot of stupid things, but their influence on society in general is more or less nil.
There is a rising group of Hispanic elites in this country who, like the Irish, Jews, Italians and every other immigrant group has done in American history, are taking a place at the table of power the old-fashioned way: politics and economics. The Aztlan jokers are just a sideshow.