I think it's because the spirits dilute the oil. It evaporates/dries up within a few days and you've lost your lubrication. It's still been cleaned so it works OK if everything is smooth inside, if not, you're back to where you started.
I learned this the hard way; never use WD-40 as a lube on a high speed shaft
I learned this the hard way; never use WD-40 as a lube on a high speed shaft
