Personally I wouldn’t say anything, for two reasons.
1. There are a lot of weirdos riding around and who knows what they would do in a case like this. Many of them are armed.
2. Would I want someone yelling at me for any political stickers or signs affixed to my vehicle? (I don’t have any). Absolutely not. If some lefty loon yelled at me at a light, I would be pissed but I wouldn’t respond. What does it accomplish? Nothing.
Your reply precisely explains why the small minority of leftist thugs in the West rule the roost. Never again will I grin and bear it when faced with leftists and there intimidating bullshit. Never, and under no circumstances, will I ever go silent again or bite my tongue again. They throw it my way I’m throwing it back in spades. We all need to do that now or we will end up their subjects. Overwhelmingly, leftists are cowards. Push back and they crumble. Cower and they conquer