Wicked: For Good

I’m not sure if I really “get” Wicked: For Good. I think it’s an allegory or a fable about something? Exclusion? Discrimination? “Otherness”? The music is undeniably beautiful. But I’m not entirely sure what they’re singing about. Do I need to dig around for the Frank Baum source material to understand it? Or maybe check the revisionist novel on which the Broadway musical is based? It’s beautifully designed and filmed. People flying around, people yelling, people in jeopardy. Funky steam-punk gears and stuff. But I’m not sure I get what the blonde lady and the green lady want. They sing and cry a lot. The green lady is mad at the wizard, who’s a jerk. The vocals are perfect. There’s not one sour note in this entire musical endeavor, but I have trouble connecting to the underlying moral. Should I just shut up and "follow-follow-follow-follow, follow the yellow-brick-road"?