From drying clothes to getting the right nutrition, there are clearly superior and inferior ways to do get any particular result. But of course people don't have the knowledge/skills to figure it out for themselves and come to that judgement on their own. Instead, they use monetary value (price etc) associated a particular method as a proxy for superior/inferior. Once you are down this slippery slope, it is easy to jump the next few steps of this lazy-yet-practical logical staircase that leads to class hierarchy in society and what outwardly behavior brings class status in your society etc. Since these implicit logical models are taught and reinforced generationally, only generational shifts can break the cycle and that makes it hard to change the stereotypes.