Earlier quoted context omitted.
That's exactly why those are all examples of bad laws.
So how would you propose legislating them? Or are you suggesting that there should be no limit at all on what is available or permissible, or of age? Case law and precedent generally makes it clear enough, and adapts to changing expectations without needing to be rewritten. It may adapt slower than many would like. Doesn't make the laws bad. Every country has some limits, and standards for movie ratings and age restr…
If some legislation cannot be so rewritten, it should be thrown out. Yes, that goes for anything with "vulgar" or "indecent" in the title.
Speaking of standards for movie ratings - they aren't law in US, just industry guidelines. So they're subjective, but people have a choice of following them (e.g. because they believe the board that rates stuff has the same subjective opinion of what is "inappropriate" as they do) or not. Similarly, movie makers can, and do, release unrated movies. Since it's all voluntary, there's no problem here.