I bet that even on HN there are a fair number of people who would disagree with each other whether or not the "Boycott Israel" movement is engaging in hate speech.
In America, there are active efforts by members of the government to classify Antifa as a hate group. Facebook famously got a lot of flack over their decisions about whether or not "white men" count as a protected category. And again, I wouldn't be surprised if there are people on HN who disagree over whether or not protected categories should be extended to historically privileged groups.
The thing is, ignoring intrinsic rights, both free speech and censorship are still neutral tools. Regardless of what direction you lean, there will be efforts by the powerful to use the tools you embrace to suppress others. The conflict is figuring out what the proper balance is to make it difficult to abuse those neutral tools.
But it's not simple to claim, "people should only be allowed to say good things," for the same reason why it's not simple to claim, "only the government should be able to unlock my phone." You have to figure out where to draw a line between encryption and warrants, bearing in mind that corrupt individuals will take advantage of both.
The examples that GP linked were decided against far-left activists based on the idea that free speech wasn't absolute. Many of them are regarded as negative precedents now, moments in history that we're ashamed of. I'm ashamed that America tried to use the law to prevent people from protesting the draft.
Of course free speech isn't absolute. But that doesn't mean that discussions about how far we should go are meaningless, or that anyone who suggests that a law is too restrictive is actually just a secret absolutist. Historically, free speech rights in the US have grown over time, not shrunk. That suggests that as far the US is concerned, we think that historically we didn't take those rights far enough -- and usually whenever we put limits on free speech we did so to the exclusion of good faith protesters and minorities.
This makes many 1A advocates nervous about reintroducing those limits, because a large portion of the examples we have about enforcement of those limits in the past were used to suppress and harm activists.
Of course it's reasonable to disagree on that front; you probably have experiences in your own life that have convinced you that the European model is better. Those differing experiences are a good reason for us to look for laws that respect national autonomy where possible.