No, you had precession correct. Precession of the pedal axle threads in the crank will tend to tighten as a result of your pedaling action. It was a definite problem when I converted our tandem to a 'kid-back' type and used a child crankset flipped so the chainring was on the left side. As a result, the left pedal was right-hand thread and vice versa which resulted in a strong tendency for the pedals to loosen up due to precession.

OTOH, bearing friction in the pedals using the normal left pedal = left-hand thread system will tend to loosen the pedal. With good, properly working pedals this is usually a smaller effect than that of precession. But apparently not with the cheap bushing-bearing pedals seen by SBinNYC.