The point, though, is that these plates are supported by those who buy them, not your tax dollars. This is about what speech the state will ALLOW.
Nothing prevents private citizens from adding whatever political statements they want via bumper stickers, signs, etc. I certainly don’t agree with the pro-death crowd, but we can’t banish political opinions we disagree with. If we allow pro-life statements on government issued plates, we have to allow the alternate. How would you feel if the situation was reversed?