According to whom? The organization that can't distinguish bad actors from good? I mean, you may be right, but he point is, they could do it, they just choose not to because it would be unprofitable.
By the way, this is already done since Google does check advertiser accounts against various sanctions and watchlists as part of dosing business in every country they operate in.
The point is that it’s not a resource or scale issue (as you keep arguing), but a profit and incentives issue as I said before.