> Do you mean that it’s more reliable to discern the truth from ads than when the bias isn’t clear?
No, I think that it's easier to reject (overt) ads manipulation because their bias is clear, compared to forms of manipulation where the goal of the manipulation is less clear; this doesn't help you get to the truth (except in some cases where that is revealed by what even the ad is forced to admit against its interest, or hinted at by what it avoids) from the ad content itself.