It's pretty standard to include your funding sources in your publications, and some see it as morally imperative. That it was not included is suspicious. But yes, it's an additional safeguard on that filter. And I think you give the whole system a little more credit than it deserves. At the end of the day, the publishers need to make money and they need papers to publish. Don't just assume that just because something is published in a peer reviewed journal that it meets the highest standards of quality. It's very often not the case.