Define 'facts' and then define 'lies'...There are a lot of unfounded conspiracy theories on many things, including vaccines. Such can be very damaging on take up of vaccinations generally, so I believe the wildest of them should to be stamped on quickly. Free speech is good, but only if based on facts. Many people are simply unable to determine genuine facts from lies.
When you state that 'the wildest of them should to be stamped on quickly', where do you draw the line and who defines where the line is drawn?
What you are actually saying is that free speech should be curtailed for the 'public good' - but only when you agree with what should be curtailed!
Slippery slope!