I think its a bit more complicated than this. Disputed outcomes are decided by votes from UMA token holders, which are anonymously owned. I remember reading a theory (with evidence, can't find the article now) that the venn diagram between Polymarket owners/stakeholders and UMA whales is close to a circle.

I am surprised to learn this.

Can you influence outcomes on Polymarket by purchasing enough UMA tokens?

Why would people accept this? Especially if ownership is anonymous and could overlap with market actors?

For the same people accept Tether's claims of solvency even though they refuse audits and obviously lie about ownership of various assets. For the same reason people ignore wash trading. For the same reason people continue using Sam-coins even after FTX's implosion.

Because A) they're not paying attention, B) they're in denial and C) because they think they can profit in the short term before it collapses, or that the odds are in their favor to profit despite the risks.

People will accept it as long as it mostly operates in an expected manner and they get their payout.

People are very good at convincing themselves that because something has not happened, therefore it will not.

When UMA is eventually abused to make a lot of money, then perhaps things will change.

But it will feel pressure from a certain government that want's to convince people that it did not "invade" but rather "policed" Venezuela.

I don't think this government particularily cares about convincing people about anything, they are just doing whatever they want public opinion be damned.

Maybe.

I've found that dishonest bookies will commonly bet when they have insider information or some way to push the outcome in one direction.

That's why the mob both employs bookies and pays boxers to throw fights.