IMHO
The Customer Is Not Always Right: Here Are Five Reasons Why outlines part of the reason for this. The other, and related part, is in trying to cater to the unreasonable customer too many companies treat their employees like crap. If the company don't support you when you are in the right then why should you support the company?
"If we adopt the policy of admitting whatever claims the customer makes to be proper, and if we always settle them at face value, we shall be subjected to inevitable losses." - Farrington, Frank (1914). "Successful Salesmanship: Is the Customer Always Right?".
Mill Supplies. Vol. 4 no. 9. pp. 45–47. A year later there was Farrington, Frank (1915). "Is the Customer Always Right?".
Merck Report. Vol. 24. pp. 134–135. which covered much the same ground.
Too many companies are so afraid of loosing a customer that they will cave in to the most insane demands forgetting there are those who will game the system. My boss described one such situation when the hotel chain he worked for had one of those 100% satisfaction guaranteed promotions and this one couple literally went from one end of the US to the other using that promotion get free rooms.