It makes it sound like the customers are some clearly identifiable and reachable group of people all gathering outside just waiting for you to go talk to them.

For some businesses that may to some degree be the case. For many businesses that is not the case, although their customers can be defined they may not be easily or cheaply reachable. They may not all fall under the same category despite all sharing some fundamental problems for which the company is providing a solution.

So casually saying "just go talk to your customers" is about as helpful as saying "just go build your business".