I’m sorry but liberal democracy isn’t the best form of government because the people are smart (they never have been), it’s the best form of government because the alternative is recurring political violence.
I don't want to assume you're American, but your fatalistic view of government sure does point towards that. I suggest you spend some time looking at how other liberal democracies handle this challenge. Online political advertising remains a challenge everywhere but usually the same legal and ethical frameworks apply—even if the frameworks still fail at the margins.
And to be clear, my objection isn't to all online advertising but specifically to Zuckerberg defending Facebook's stance by appealing to free speech. I don't think any Government should force Facebook's hand; I think they should seek to protect their social license and act independently as Jack Dorsey recently did.
I wouldn’t trust anyone who wanted to be the censor to be the censor.
Separately, while some politics revolves around untestable statements of preference (e.g. Purple team “freedom is more important than equality” vs. Teal team “equality is the best foundation upon which freedom can be built”), there are also statements of fact and it is dangerous to allow demonstrably false claims to spread (Antivaxxers are probably the least controversial example of a dangerously wrong meme on this forum, but others exist all the way back to ancient Greek democracy).
Democracy isn’t Magic: If Antivaxxers got 99.9% of the votes they would still be wrong, the only difference is they would cause more harm.
It's not a coherent comment in the context of the US 1st amendment.
And by the way, the First Amendment disallows not only prior restraint, but many other government restraints on speech as well. It's just that prior restraint is considered the most egregious and hence subject to the greatest judicial scrutiny.