I disagree. It's not just the purview of software engineers to understand or see how the company's product helps the customer. Lots of roles need to come together to create a successful product. Generally speaking, the employees that signal their passion for the given company/product/mission/etc are the one's more easily leveraged for longer hours, less pay and more work. As someone else mentioned here, be professional over passionate. The company isn't as passionate about the employee as the passionate employee is about the company. I can guarantee you that.