I agree about most disgruntled people being ones who got rejected or got in on holistic basis and couldn’t rise to handle top notch academics. Pre-Med is a competitive track at every college and obviously more so where everyone is a high achiever but that’s also the reason behind higher academic standards of these colleges.
I partially agree with your second comment about different colleges offering different strengths but overall students at competitive residential colleges tend to be happier. Not saying you can’t be happy at JHU or are guaranteed happiness at another college. Pre-Med is competitive everywhere.