There's a better version of this "I just moved and haven't had enough coffee" post to be written, but my take is that while I'm not particularly bothered by minor speech restrictions in other countries I would be bothered by them here. That is, while I agree that they aren't necessarily a slippery slope in other countries, I think they'd be more likely to be one here. Free Speech is an American norm in away that some of our other claimed rights aren't in that generally elites are on board with it in a way that they aren't necessarily, say, on board with strong interpretation of 4th amendment rights. I'd be quite worried if the legs started to be knocked out from under it because it would signal a big change in prevailing attitudes. While enacting such laws might not automatically send you down the slippery slope, I think if we started doing so it would signal that we'd already started heading down it.
It's a right we're holding onto fairly well, and I'd be worried if we started to lose it even a bit.
