Freedom exists only to the extent that other people cooperate with it. Safe spaces are inherently a form of restriction of freedom.
In a classical liberal context, freedom is a property of the will of the individual and therefore a natural right. my understanding is that it does not diminish simply because others do not co-operate with it. The form of freedom you are talking about is clearly not a liberal one.
Do they? Under which circunstances, and why exactly?
We do not exist in a world that enables us all to act as inconsequential children. Our actions and omissions, right or wrong, fairly or unfairly, have consequences on others.
On the general case, we definitely do not have such a right. On the contrary, there is a moral duty to address criticism to the better of our abilities.
We have a duty
to ourselves to be rational, given that we will individually suffer the consequences of our own irrationality. Whilst I can certainly appreciate the frustration and difficulty in dealing with the irrationality of other people, unless it extends directly to a form of harm, it is generally not within an accepted scope of a person to do anything about it because it impedes a person's autonomy.
If the laws are set up in such a way for those specific individuals, sure. But that is not the level of discussion that interests me in this thread. Law is just law. It has no moral significance and no reason nor wisdom of its own.
I am interested in the practical significance, justification and consequences of safe spaces and of their absence. Law is immaterial for that, or at most comes as a consequence of taking some stance on those matters.
I would understand "freedom of speech" as a
legal condition, whereas clearly you do not here. If we are talking about practical terms, we are not talking about the rights of individuals to autonomy as written in the law. We are talking about power relations in society. In the context of criticism, you are essentially saying that one person has the power to criticise another and they have the obligation to accept it. Would that be an unfair characterisation?
Trouble is, your premise is that individuals do not owe anything to the world that we live in. And that is all-out ficticious and unsustainable.
There is a significant difference between saying we "owe" the world for material goods that are produced, and saying that the inner contents of our minds and experiences are "owed" to someone else. It is a point of departure into distinctly illiberal and collectivist modes of thought.
Your essentially arguing against the individuals
freedom of thought and that the will of an individual to think is subject to a social obligations. That may be unfair and you are free to argue against such a characterisation of your position. I would urge caution if however that is a more accurate representation of the logical effect of an obligation to respond to criticism. Arguing against another person's free thought typically becomes a weapon against our own.