Hmm... Can't tell if you're agreeing or sarcastically and incorrectly pointing out a logical fallacy. If you agree, cool. If not:

The Slippery Slope fallacy is only a fallacy if one posits that the future events MUST happen as a result, not that they are likely to. If I take a step further down a literal slippery slope, I am more likely to fall but not guaranteed. If you start using hardcore drugs, you are likely to get addicted and lose a lot of money but again, not guaranteed.

That this would set a dangerous precedent is not a slippery slope argument in the slightest. Courts frequently have to bear in mind the legal precedent of their actions because once you do something, its easier the next time. That is fact, not conjecture. It is easier to ratchet down on a freedom that is already jeopardized. No conjecture involved there. No slippery slopes involved. If we allow some speech to be censored, it becomes easier to censor other types of speech.