I disagree. I don't think many people at all try to become ridiculously thin. Plus, such attempts rarely lead to good health, which is why eating disorders are such a big issue.
Just as "ridiculously rich" is relative (for some people in 3rd world countries it could be having a few thousand dollars) so is "ridiculously thin" (for someone weighing 350 pounds this could be weighing 250 pounds). And I would argue that achieving this goal, in general, leads to better health. This is not to say that exceptions which lead to poor results don't exist in both cases, which makes the correlation even stronger.
You're stretching this metaphor further and further into absurdity. The author of the post wonders why "wealth anorexia" doesn't get similar attention to that of actual anorexia. The answer is because anorexia actually has negative effects on the lives of many people. "Wealth anorexia" does not.
Trying extremely hard is not without health risks, physiological and psychological.