because it's good for you
The ultimate b**ls**t reason that someone in authority impatiently tells you to forcibly pressure you to consume/do something you detest, such as insipidly chomp through a huge bowl of oatmeal, choke down hard/sticky/bitter medicine-pills/powder/syrup, bake in the sun for extended periods, attend school/church, meet/interact with someone whom you fear/dislike, or any other acutely-disagreeable action of dubious --- and still largely unproven, in many cases --- effectiveness or benefit.
Using the age-old "because it's good for you" reasoning to convince someone to perform one or more disagreeable tasks --- especially if you cannot be totally certain that said procedure actually is indeed necessary/appropriate/effective for that particular person, and in those particular circumstances --- has always been an unwise and hurtful procedure; not only may it needlessly subject the "sufferer" to untold misery, but it also can often cause the agonized "victim" to totally turn away from and obsessively do the exact opposite of said practices/procedures (such as entirely shunning "health foods" like vegetables in favor of junk foods like chips and soda, or tempestuously refusing to hear or discuss anything even remotely alluding to religion) just as soon as he gets old enough to begin making his own decisions, and cause him to live an exceedingly unhealthy and "intellectually isolated" lifestyle. Plus it is an especially tragic mistake in current times, when there now exist so many far-more-palatable alternatives to the "basic 'n' boring" past methods of carrying out said "necessary tortures", such as using fun educational videos instead of having to tediously bury one's nose in a dusty book, or administering pleasant-flavored herbal/medicinal beverages instead of following a horridly "strict 'n' mundane" Puritan-type diet.