bmyer- mik5 is referring to people who do eat processed foods year-round but not on Pesach. So it seems that there are hashgachos that they do rely on year-round but not on Pesach. Which hashgachos those are is not relevant to the discussion, and OU was apparently just brought in as an example.
(and let’s try to be careful that this discussion doesn’t c”v end up leading to motzi shem ra about specific hashgachos!)