See, Marge, strangling the boy has paid off," Homer quipped to his wife. "Just kidding. I don't do that anymore."
Homer then added with a smile, "Times have changed!"
I think it's a joke about liberal virtue signaling. He doesn't understand why times have changed nor does he tackle morality in his reasoning, he's just an idiot. But times have changed, so he's less abhorrent now.
This protest is aimed at the government, not US society. While not the most radical, its important to show just how many people care about this cause.