You can’t really be a true supporter of free speech but then ask in the same sentence for threads to be shut down that you don’t like. It’s fine to be in favour of some kind of censorship and I would not disagree that it is actually a good thing in quite a lot of situations, but we do need to be honest about it.
That said, do you honestly think that shutting down these threads will make things better or worse? Because when people see that they aren’t allowed to express their opinions, it generally entrenches them rather than causing people to rethink them.
Isn’t it better to remind these people that the stories about benefit scroungers are hugely exaggerated by the right wing press and that their are many, many real people using the system in exactly the way it is supposed to work? That if there are more people claiming disability, particularly when it comes to mental health, it is because it is a rational response to the rotten state of our society and our economic system?
You’ll probably struggle to persuade many of them, but there are those that aren’t sure what to believe where threads like this one and comments on other, less friendly threads may make a difference.
Suppressing things generally makes them worse - confronting often makes them better.