Amongst other things.
Our Western culture, our society, and our lifestyles have evolved. In the distant past, physical health wasn't for people who could "make the time", or strictly for those who "enjoyed it" - it was the necessary standard. Those who lacked it were, in Darwinian fashion, eliminated. As science and technology improved, ironically, it meant we had to do less and less - and now we see people living longer than ever before. But what quality is this extended life? Attached to machines, moving with extra supports or aids - if it is the result of disease or injury, then that's one thing. But if it's simply because we felt exercise was too low a priority - well, shame on us.
I read a metaphor a couple of years ago, and to be honest, I don't remember precisely who it was that said it. I think it was Michael Boyle, although I may be wrong - and if the individual whom I'm taking this from reads this blog, feel free to correct me. But essentially, the question was - what if you received one car your whole life. You were given it very young, but it was the only one you were ever going to own. Take care of it - oil change, rotate the tires, 2x per year overall maintenance - and you would still have a dependable vehicle to get you from A to B when you were 90 years old. But ignore these maintenance routines, and just drive it until it gives out - well, you're going to be without a car by the time you're in your mid-30s. Or, at best, you're going to be trying desperately to salvage what is left and hoping to keep it running in some form. If this were the choice, what would you do?
Your body is your vehicle, and you only have one for your whole life - treat it with some respect, before it's too late.