I was one of the close-voters and I thought this question sat squarely on the line -- I voted to close expecting a meta discussion, which is good at this stage in the game.
I think I voted it as off-topic, but I was choosing between off-topic, too localized, and not constructive. That right there says the question needs some work.
If this were a question that led with a general workplace issue (supporting a product you don't believe in? -- I know that's not at issue in this particular question, but would be a general concern) and used a specific example that was not the only example, then that would be great. To wit, one commenter noted a phrasing such as "How do I handle [this new job responsibility] when I have severe doubts about its efficacy (and here's why)?" -- if that were the question, and the example was given, I believe that would be a good question, because it would not be specific to sales, just applicable to sales (and other positions).
But in this particular case, there are a lot of unknowns -- as a commenter pointed out, " [the answer] varies by the medium involved, ie telephone, retail business, door to door... etc."
That was my thought process, at least.