Freedom of speech includes the right to tell lies - because truth, in a lot of cases is subjective and people often don't know they're telling lies.

In your examples what is really being prosecuted is the crime committed after the speech. If you base your actions on the mistruths of others (by storming the capitol building) then you become complicit in an action for which you are partly responsible. That's on you. If you give someone a bag of rocks and say 'these are potatoes' no crime has been committed, if you sell them a bag of rocks in lieu of potatoes then the crime you'll be prosecuted for is theft. Likewise, shouting 'fire' in a crowded theatre, what you're prosecuted for is the actions which stem from it.

I don't really have a problem with people being prosecuted for negligence, stupidity, theft, incitement or any other thing we have agreed in law. I have a problem with people pre-agreeing what constitutes negligence, stupidity, theft and incitement and not letting me know how that decision was reached. I don't want decisions made by social pressure, I want them made by clear adherence to principles in law and for the benefit of society.

I think the ideal situation is the one you've described, you make Twitter (or any social media platform) a co-defendent in every single case of libel, you make them a party to any class action lawsuit in which social media played a part in any crime. I'd have exactly zero problem with that. It'd likely kill social media (which is no bad thing in my opinion) and it'd make people stop and think harder about the consequences of what they write.

I'm all for that. :o)