Rather than say avoiding customer feedback altogether, I'd say to use it appropriately.

Whether you're using "Lean Startup" or traditional product development, you're going to encounter people who say "I want feature X". Rather than simply taking this as a request for a feature, you should act as if they said "I am trying to do something with your software, but I can't, and I think that if I had feature X I could do it."

Figuring out what that something that the customer is trying to do is invaluable. Then you need to figure out if you're going to help them do that something or not, and how to do it.