It’s like saying “the nerve of it all/the cheek of it” which means similar to “how dare they”.

I think the character is looking around a room full of shady (non trustworthy) characters and says “the shade, the shade of it all” which I think means “look at all the shady/bad characters here”

The shade of it all" is a phrase from drag culture, often used on shows like "RuPaul's Drag Race." It refers to playful or witty criticism, sarcasm, or insults (also called "throwing shade"). It's usually said in a humorous, exaggerated way to highlight how clever or cutting the remark was.