Keep in mind I'm European, and not American. I think we have a different view on this. Especially e.g. countries with a coloured history of hate speech like Germany.
1. Ideas need to be open so they can be challenged: These platforms don't create discussions, they create echo chambers. Nobody of their right mind engages with the crazies online as it's obviously a waste of time. Try to go to Facebook and debate with any of their "Flat earth" groups. It's absolutely futile. These "debates" are better for recruiting new people into hateful ideology than building understanding.
2. "Free speech" something or another: There is no such thing as "free speech" because there are already limits to speech. We've already drawn an arbitrary line on what's legal and harassment, death threats, racism, discrimination, defamation and multitudes of other types of speech are already controlled. If something is illegal to say to someones face, why should it be legal to say online? Not to mention that discussions about free speech spans borders and laws are different across them.
3. Who defines what's hate speech? I'm not an American, but I am at the mercy of your platforms. I for one would much rather that at EU-based body, or my government (I know this sounds crazy for an American, but we have more trust in our institutions) decides what's OK to say rather than tech billionaires like Elon Musk, Mark Zuckerberg, or Sundar Pichai. These people are already making moderation decisions, which is inevitable with large-scale social media. Make these policy decisions openly. Make them democratically.
Large scale social media platforms are cesspools already. Unmoderated social platforms turn into cesspools by default. Moderation of these platforms must be moved out of private companies and into the public sphere so we as a society can agree on what is right, and what is wrong.