Why should Facebook (or any other platform) be accountable to anyone in particular for what the users of the platform say?
I get that, now, they've hoisted themselves by their own petard after years of inconsistent policies and enforcement, but I mean in a general sense.
>What does holding them accountable look like to you?
The opening paragraph of section 230 of the CDA, to wit:
"No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider"
There be far worse dragons than disinformation down the other roads. Let's take this to its logical conclusion - you've got people on the left upset about "conspiracy theories" (which is, itself, a pejorative term with problematic origins rooted in thought control), you've got people on the right upset about "bias" against their stances.
When both sides of the political aisle are demanding tighter control over speech for any reason, the intended result should terrify the hell out of you.
The problem you speak of is not "people say false things" (which is not solvable), the problem should rather be seen as "people demand the ability to censor people they disagree with". The solution to that problem is telling both sides to pound sand and take responsibility for their own beliefs, not foisting that responsibility off onto third parties in a way that necessarily restricts freedom of speech.