Christians, Muslims, and other religions use fasting for spiritual reasons, as you probably know. These people believe that the spiritual is above and beyond the physical. There's no reason to apologize for such beliefs. Most believe that we exist as body, mind, and soul, with the body being the least important of the three.
Gandhi fasted for political reasons. Not just to lose a little of that belly fat. I would say that making a political statement is a higher calling for fasting than just trying to tone up so you will look better at the clubs.
For those who fast for their personal physical gain, that's great. But there are higher reasons to fast.
Hopefully all who are fasting for whatever reason are inspiring others to follow suit. If you are fasting for selfish reasons but you are inspiring others, then you are making a difference.