Well relative to the thread and often times it’s seen as a kick start to fitness which I generally think is silly. I think that’s where the derision comes from.Some people fast for spiritual reasons (e.g. Jesus 40 day fast)
Some to push their limits. Some to develop discipline. Some just to get mental clarity.
I fasted once for about 3 days and by the 2nd day, although I was mad hungry, I was mentally sharp. For Lent I’d do a 12 hr fast of just water.
I read when Obama started to turn his life around while at Columbia (eg less smoking, partying etc), he’d fast every Friday as a way to discipline himself.
Going a few weeks without food shouldn’t be met with such derision imho
The other stuff I you mention above I don’t disagree with FWIW.