The fact that you are in pain every day is obviously a tragedy, and I hope your situation improves. Mocking your peers for taking care of themselves is still not acceptable, and does nothing to improve the situation for anyone.

I accept that this is a spectrum, and that some level of discomfort in life is unavoidable—people stay up late and skip exercise from time to time. The unpleasant consequences of these actions doesn't justify not contributing to society, and there are no doubt freeloaders in any reasonably sized company.

However, no workplace, including yours, should expect their employees to sacrifice their health.