Given that people pay to advertise on facebook, any false statements they make about their moderation systems via the internet almost certainly constitute wire fraud.

You make that claim with a high level of confidence, but have you actually read the contract in place between Meta and the advertiser?

No, but I've read the relevant section of the USC. Statutes override contracts, you can't contract out of being bound by the law of the land.

It would almost certainly not.

As Matt Levine says, “everything is securities fraud,” and this is probably the area of greatest exposure for a company with a substantial degree of departure between their stated practices and their actual practices.

It’s not likely to be more than a nuisance to defend and not terribly expensive to settle, but an enterprising plaintiff’s lawyer could probably find a cause of action that passes summary judgment.