I think it's a genuinely dangerous slippery slope.
This "slippery slope" meme seems to be the libertarian's favorite argument against any legislation, but how do things actually happen in the real world? Certain people behave in ways that happen to be legal but which most of us find immoral (which, in fact, most of the perpetrators would find pretty nasty themselves, if it were to happen to them). So, we change the law and ban something. Libertarians immediately extrapolate the new legislation to a ridiculous extent (straw man argument) and thusly "prove" that even the non-exaggerated legislation is wrong. The rest of us ignore the screechy libertarians, and wait for any actual *evidence* that the new law is abused, and, lacking such evidence, sleep soundly at night. Many countries in Europe have limitations on public speech that would give a U.S. constitutional fanatic a brain embolism, and yet magically Europe persists in being a place of open discourse, not a police state. So, relax, and give some thought to the people that some of these "dangerous" laws are actually meant to protect.