In the context of the 'Guerra Cristera', PJT's intepretation must be correct. Yet, I'd say the neither the song, nor the movie have much to do the 'Cristeros'; since I don't know the book, I have no idea where or how they're involved in the story.
That said, the movie is the story of a man whose parents were murdered when he was a baby, and he grows up to become the paragon of the Mexican 'Charro': brave, manly, honest, honorable, good with guns...
As for the song, like most of the 'Rancheras', has extremely simple lyrics (and often they don't have to make much sense); it's even said that Jorge Negrete (the actor who played the main character in the movie) hated to sing it because he thought it was ridiculous.
Finally, "rajarse" means to chickent out (the origin of the expression is to lose a man's virility), and the Mexican 'Charro' archetype comes from Jalisco, where the 'Charrería' (the Mexican sport involving mastery of horse riding and cattle wrestling, similar to American Rodeo) was born.
So, as far as I understand, the expression "¡Ay, Jalisco, no te rajes!" in the song, more than "expecting something" from the state of Jalisco, is a celebration of the qualities of the territory, but mostly a praise of the bravery of the 'charro' himself, who is not shrinking to face his enemies, and he's ready to kill or to die for his honor.
__________________
♪ ♫ ♪ Ain't it wonderful to be alive when the Rock'n'Roll plays... ♪ ♫ ♪
|