Indeed, they are supposed to be salesman, peddling a product. If a salesperson sells cod liver oil, it doesn't mean they have to love the taste. Its their ability to sell that is attractive. But that basic idea does not translate to the entertainment industry. This is the same person who decided to represent you because they believed in your ability, or so you thought.
Insecurity permeates the industry.
Interestingly enough, these managers and agents need constant validation and reinforcement of their opinions. The ONLY thing that matters to them is their commission. Yes, it is true. Most agents would have you believe that you work for them, especially when you are a new, unsold, or unproduced writer. But such is simply not the case.