On one hand, America was built on the values of free speech, which are obviously important. We cannot control what people are saying or our democracy falls apart. On the other hand, allowing harassment has a stifling effect on free speech, because it allows people to be bullied into silence. Before the internet, this distinction was fairly simple: Someone with a megaphone screaming hate speech in a park is exercising their right to free speech. Someone with a megaphone following a guy down the street is harassing them.
The arrival of the internet has made this line much more vague. However, the line between free speech and harassment is not nearly as blurry as some people might think. Our concept of reasonable freedom of speech is guided primarily by our ability to ignore it. The idea is, someone can go to a public park and say whatever they want, because other people can simply go somewhere else. As long as people have the ability to ignore whatever you're saying, you can say pretty much whatever you want. We have some additional controls on this for safety reasons, so you can't go to a park and talk about how you're going to kill all the gay people, tomorrow, with a shotgun, because that is a death threat.
Unfortunately, in the midst of defending free speech, a disturbing number of people have gotten it into their heads that other people aren't allowed to ignore them. This is harassment. The moment you take away someone's right to ignore what you are saying, you have crossed the line from free speech into harassment. Freedom of speech means that you have the right to say whatever you want, and everyone else has the right to ignore you. I'm not entirely sure why people think that free speech somehow lets them bypass blocking on a social network. Blocking people on the internet is what gives us our ability to ignore them. Blocking someone on the internet is the equivalent of walking away from some guy in the park who was yelling obscenities at you. If you bypass the blocking mechanism, this is basically chasing them down as they run to their car, screaming your opinions at them with a megaphone. Most societies think this is completely unacceptable behavior in real life, and it should be just as unacceptable on the internet.
On the other hand, enforcing political correctness is censorship. Political correctness is obviously something that should be encouraged, but enforcing it when someone is saying things you don't like in a public place is a clear violation of free speech. This is not a blurry line. This is not vague. If a Nazi supporter is saying how much they hate Jews, and they are not targeting this message at any one individual, this is clearly protected free speech. Now, if the Nazi is actually saying we should murder all of the Jews, this turns into hate speech because it is inciting violence against a group of people, and is restricted for the same safety reasons that prevent you from shouting "FIRE!" in a crowded movie theater.
Now, what if the Nazi supporter tells a specific person they are a dirty Jew? This gets into fuzzy territory. On one hand, we can say it isn't harassment so long as the targeted person can block the Nazi and the Nazi never attempts to circumvent this, or we can start classifying certain speech as being harassment if it is ever targeted at a specific individual. When we are debating what counts as harassment, this is the kind of stuff we should be debating. This is what society needs to figure out. Arguing that mass-block lists on twitter are hurting free speech is absurd. If someone wants to disregard everything you're saying because you happen to be walking past a group of Nazi supporters, they have a right to do that. If someone wants to ignore everyone else on the planet, they have a right to do that.
This kind of stuff is a problem when the vast majority of humanity uses a single private platform to espouse their opinions. Namely, Facebook. This is because Facebook has recently been banning people for saying faggot, and because it's a private company, this is completely legal. This is also harmful to free speech. What appears to be happening is that websites, in an attempt to crack down on harassment, have instead accidentally started cracking down on free speech by outright banning people who say hateful things, instead of focusing on people who say hateful things to specific individuals.
Both sides of the debate are to blame for this. Extreme harassment on the internet has caused a backlash, resulting in a politically correct movement that calls for tempering all speech that might be even slightly offensive to anyone. In response, free speech advocates overreact and start attacking them by bypassing blocking mechanisms and harassing their members. This causes SJWs to overcompensate and start clamping down on all hateful speech, even hateful speech that is clearly protected free speech and has nothing to do with harassment. This just pisses off the free speech movement even more, causing them to oppose any restrictions on free speech, even reasonable ones. This just encourages SJWs to censor even more stuff in an endless spiral of aggression and escalation, until on one side, everyone is screaming obscenities and racial slurs in an incoherent cacophony, and on the other side, no one is saying anything at all.
If society is going to make any progress on this at all, we need to hammer out precisely what constitutes harassment and what is protected free speech. We need to make it absolutely clear that you can only harass an individual, and that everyone has the right to a block button. If a Nazi supporter starts screaming at you on twitter, you have the right to block him, and he has the right to block you. We cannot solve harassment with censorship. Instead of banning people we disagree with, we need to focus on building tools that let us ignore people we don't want to listen to. If you object to everyone blocking you because you use insulting racial epithets all the time, maybe you should stop doing that, and perhaps some of them might actually listen to you.
Of course, if you disagree with me, you are welcome to exercise your right to tell me exactly how much you hate my guts and want me to die in the comments section below, and I will exercise my right to completely ignore everything you say.