Problem is that a lot of people seem to equate physical endurance to health. Great for you if you can walk miles without rest, but if you are obese it'll still drastically increase your risk of heart faliure, diabetes, liver problems etc.
In the UK, it pisses me off a little when people say 'if i'm happy with myself it doesn't matter if i'm fat' because we have nationalised healthcare. I love having the NHS, but I feel like people who wilfully live unhealthy lifestyles and demand NHS treatment for the myriad of conditions that they will experience are just putting extra strain on an already overstressed service at the cost of everyone else. If they pay for the inevitable extra workload, then fine; if healthcare is entirely privatised where you are, then great. if not, then it's a bit selfish to live in a way that's going to screw over the healthcare system if it is possible for you to get healthy.