[surge]

Free speech is a pressure release valve for society. Otherwise, people just keep quiet until they explode, many times in a mob because they feel no one is listening or they're being suppressed, or ignored by media, politicians, etc. For example, it is far better someone goes and complains about immigrants online and vent frustrations, even if half of what they say is racist or unjustified, because they at least are venting frustration non-violently and maybe, just maybe some of their concerns or points or personal experiences are legitimate and need to be addressed even if it's not with the solution they're suggesting. If nothing else, you know that person exists, and they're on your radar if they start expressing violent intentions.

Also, the answer isn't to suppress speech so it goes and hides under the surface, it doesn't go away and the people exposed to it never hear the counter points. The communities you talk about, like reddit, hate speech gets downvoted, it gets counter argued. Bring dumb hateful ignorant views into the light, so they can be addressed, if not for the purpose of convincing the OP (which is often futile), convincing anyone who might be on the fence or sympathetic at least partially to some of their points can understand why its wrong. The problem is when boards or sub-reddits become insular so never face opposing views, on either side, going back into bubbles or group think does not lead to moderate opinions and compromises, just like proving someone wrong can sometimes just cause them to double down on their opinion.