Are they trying to say that a private landowner has no say on what gets posted on a billboard on his property? Sorry, no sale.
The Supreme Court made sure to draw our attention, several years ago, to a doctrine that says that contracts may not abridge articles of the Bill of Rights (as through a "black covenant", or by incorporating or referencing a "black code"). I have deed restrictions on my own property that have never been adjudicated, that restrict to whom I may sell it, but which are unenforceable under federal law.
The argument on the board, then, is whether the landowner acted improperly to abridge the First Amendment rights of persons renting space on the billboard because of "content" (as in, "vote for Bob, he's a Republican/Democrat/Libertarian"). I also have a deed restriction that purports to restrict political expression, by banning political signs in people's front yards -- I personally think that that provision is also unenforceable, but the chairman of the deed-restrictions enforcement committee, a property owners' committee supported by and reporting to the civic club (in a purely advisory way), happens to think diametrically the opposite.
So, what do you think? Did the heritage group get screwed by NASCAR and the landowner?