You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Yuan_dynasty

Context:
The historian Frederick W. Mote wrote that the usage of the term "social classes" for this system was misleading and that the position of people within the four-class system was not an indication of their actual social power and wealth, but just entailed "degrees of privilege" to which they were entitled institutionally and legally, so a person's standing within the classes was not a guarantee of their standing, since there were rich and well socially standing Chinese while there were less rich Mongol and Semu than there were Mongol and Semu who lived in poverty and were ill treated.

Question:
Who thought that the Yuan's social class system shouldn't be called social classes?

Frederick W. Mote