"Hitting children make them stronger, mothers should be hit if they disagree with that"
If an individual says this they can be discounted, but what if we let an idea take root and spread to the point that it has a significant impact in a democracy? Will they vote in the removal of human rights? Will enough of a platform exist that every jury ends up being a hung jury?
People are not perfect, independent, rational creatures. They get affected by speech. They can develop new beliefs, even a new personality as a result of speech. They can end up doing things they wouldn't even dream doing as a result of speech.
Incentivize / persuade is not identical to action. Action requires an individual act.
If we remove people from responsibility for their actions, then there is the obvious consequence that people will act more irresponsibly.
https://people.com/crime/michelle-carter-trial-gallery-key-m...
See: how the entire world treats minorities every single day.