The same argument could be made about just about any human activity that isn't obviously beneficial to humanity, the environment, etc.<p>Is reading a discussion on HN morally defensible? You could be spending that time helping humanity somehow.<p>Is working at a tech start-up making mobile apps morally defensible? You could be working at a soup kitchen instead.<p>Is playing a video game morally defensible? You could be assisting volunteering at a shelter instead.<p>Is having heat in your house morally defensible? You could be turning it off to save money which you could send to help alleviate poverty, though this will require you to endure freezing temperatures in your home.