It's hard to believe nowadays that conspiracy theories used to be a fun thing to engage with leisurely.
The issue is that they have managed to reach a critical mass where they can exert some real and harmful social and political influence.
What's more harmful? That basic freedom to believe whatever you please and share it with like-minded people without imposing on others against their will, or having legal authority to impose against such voluntary sharing for supposedly lofty ideals of fighting harmful thinking? (However you want to define harmful)