You know there is a difference between deleting posts and blocking reposts/comments/etc. or adding a link to more information about how a post is wrong.
Also, and most important, the world isn't black and white. So just because you find facebooks handling much worse then twitter doesn't mean they are happy with twitters handling, it might just not have jet overstepped their bottom line as much as facebook did.
And given that what belongs to free speech and what not isn't always clear it's really important to not see it as black and white. Not just are there different definitions of free speech (by common sense vs. by law vs. by common sense in a different country etc.). But even in this areas boundaries are not clear. The most purest form of free speech would be non constraints at all in any circumstances. But you will find it hard to find anyone supporting it (after they think about what it means). People just don't think is generally ok to use free speech to e.g. drive someone into comiting suicide.
So the real question is at which point is it free speech and at which is it "evil"/"bad"/"a crime" to a degree that it's unacceptable. And given that likely there is a lot of thinks in the gray area how to handle them the best is also not an easy question. But this is exactly where the difference between Facebook and Twitter matter, in the handling of thinks which are "bad" but not necessary so bad that most would agree it's unacceptable. Like it's a not a crime but very close to one.