Freedom of speech means there are no arbitrary government or anyone else imposed punishments for or obstacles (such as censorship) to merely talking about anything, making any public statement or publication of any information. Free speech has to be by definition absolute and have no limit, otherwise it's not free speech but controlled speech -- trying to add exceptions to free speech is like trying to limit to whom a free software license is granted; doing so immediately makes such software non-free. Free speech also comes with zero responsibility exactly by definition, as responsibility implies some forms of punishment; free speech means exactly one can say anything without fearing any burden of responsibility. Freedom of speech is an essential attribute of a mature society, sadly it hasn't been widely implemented yet and with the SJW cancer the latest trend in society is towards eliminating free speech rather than supporting it (see e.g. political correctness). Speech is being widely censored by extremist groups (e.g. LGBT and corporations, see also cancel culture) and states -- depending on country there exist laws against so called "hate speech", questioning official versions of history (see e.g. Holocaust denial laws present in many EU states), criticizing powerful people (for example it is illegal to criticize or insult that huge inbred dick Thai king), sharing of useful information such as books (copyright censorship) etc. Free speech nowadays is being eliminated by the strategy of creating an exception to free speech, usually called "hate speech", and then classifying any undesired speech under such label and silencing it.
The basic principle of free speech says that if you don't support freedom of speech which you dislike, you don't support free speech. I.e. speech that you hate does not equal hate speech.
Some idiots (like that xkcd #1357) say that free speech is only about legality, i.e. about what's merely allowed to be said by the law or what speech the law "protects". Of course, this is completely wrong and just reflects this society's obsession with law; true free speech mustn't be limited by anything -- if you're not allowed to say something, it doesn't matter too much what it is that's preventing you, your speech is not free. If for example it is theoretically legal to be politically incorrect and criticize the LGBT gospel but you de-facto can't do it because the LGBT fascist SJWs would cancel you and maybe even physically lynch you, your speech is not free. It is important to realize we mustn't tie free speech to legal definition, i.e. it isn't enough to make speech free only in legal sense -- keep in mind that a good society aims to eliminating law itself. Our goal is to make speech free culturally, i.e. teach people that we should let others speak freely, even those -- and especially those -- who we disagree with.
Free speech extends even to such actions as shouting "fire" in a crowded theatre. In a good society with free speech people don't behave like monkeys, they will not trust a mere shout without having a further proof of there actually being fire and even if they know there is fire, they will not panic as that's a retarded things to do.
Despite what the propaganda says there is no free speech in our society, the only kind of speech that is allowed is that which either has no effect or which the system desires for its benefit. Illusion of free speech is sustained by letting people speak until they actually start making a change -- once someone's speech leads to e.g. revealing state secrets or historical truths (e.g. about Holocaust, human races or government crimes -- see wikileaks) or to destabilizing economy or state, such speech is labeled "harmful" in some way (hate speech, intellectual property violation, revealing of confidential information, instigating crime, defamation etc.), censored and punished. Even though nowadays just pure censorship laws are being passed on daily basis, even in times when there are seemingly no specific censorship laws and so it seems that "we have free speech" there always exist generic laws that can be fit to any speech, such as those against "inciting violence", "terrorism", "undermining state interests", "hate speech" or any other fancy issue, which can be used to censor absolutely any speech the government pleases, even if such speech has nothing to do with said causes -- it is enough that some state lawyer can find however unlikely possible indirect link to such cause: this could of course be well seen e.g. in the cases of Covid flu or Russia-Ukraine war. Even though there were e.g. no specific laws in European countries against supporting Russia immediately after the war started, government immediately started censoring and locking up people who supported Russia on the Internet, based on the above mentioned generic laws. These laws work on the same principle as backdoor in software: they are advocated as a "safety" "feature" and allow complete takeover of the system, but are mostly unused until the right time comes, to give the users a sense of being safe ("I've been using this backdoored CPU for years and nothing happened, so it's safe"); unlike with software backdoor though the law backdoor isn't usually removed after it has been exploited, people are just too stupid to notice this and governments can get away with keeping the laws in place, so they do.
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