Safe spaces do not stifle free speech. Just as your ability to limit who enters your home (if you have one) does not stifle free speech, safe spaces do not stifle free speech.
I would argue that they actually increase freedom of speech, because they give certain individuals freedom to express themselves without fear of retribution. Something that can be rather difficult achieve for some people.
Of course, there are problems with the safe space movement. For example, they often highlight racial/ethnic/gender differences between people. In my analysis, it seems that marginalized people have realized the world is not going to change any time soon, and that they will continue to be marginalized – which is the motivation for creating a safe place.
Should Facebook/Twitter be a "safe space"? Probably not – but Facebook has been very succcesful at creating such safe spaces with their Groups platform, which seem to be gaining more and more traction.
But first, since you're defending the concept, how would you define a safe space... and how is the space kept "safe"?
The definition of a "safe space" is one where free speech is not allowed. We have had safe spaces for centuries, they are called homes. At home, you are free to shield yourself from whatever speech, ideas, or behavior you find offensive. The whole crux of a free society is the freedom to be boorish, crude, or otherwise offensive. That's what freedom means. It means there is no authority that decides what forms of speech or expression are not allowed. We already have laws against assault and harassment, and those are enough.
Yes they do. If you would like I can provide countless references and videos that showcase just how much they stifle free speech.
Yes, they do, by definition.
Are you claiming that safe-space movements that stifle free speech are justified, because someone else's free speech was stifled?
Please give us an example with details of what exactly you are talking about.