“It’s pretty lame to claim there is any first amendment right to put any lights you want in any configuration you want on a car that is driven on public streets.”
Ironic that some states would prohibit Christmas lights on my car but in all fifty states I can drive around with the word “MOTHER****ER” painted on it and that’s a protected right.
I’m not sure you wouldn’t get stopped in some states with that bumper sticker. Lights on cars are safety and signaling devices. Having extraneous lights on a car is a safety issue to not just the driver of the car but to drivers and occupants of other cars and pedestrians.
Furthermore, I just read that Texas prohibits all lights that are not federal DOT or SAE approved. I can guarantee that no Christmas lights manufacturers pay for DOT SAE certification.