That "turned from jokes into full on manifestos" part is kind of the key, but it's not like stickers changed all at once. Pickup lines have always been where parents yell their whole personality out the window, just slower now. I remember when the worst you'd see was a "My kid beat up your honor student" gag or a coexist sticker, and that was it. Now it's paragraphs, QR codes, three different causes stacked in the corner of the rear window. The jokes didn't die, they just got buried under people who can't fit their whole take on one bumper.