The phrase itself about the “monthly payment trap” is correct, this is indeed what unprofitable deals are often based on. But reducing everything to “simplicity of thinking” is also not entirely correctMonthly payment is the trap; that’s how simple minded people end up with 96 month loans at 10% interest with a vehicle that sold for 2k over sticker!
In fact, the problem is that people are deliberately led to choose through a convenient payment: they extend the term, add a high percentage, add a markup to the price of the car, and in the end the final overpayment is not at all obvious at first glance