I used to think like you wrt the social media conditioning, however now that I've experienced IBS on myself I changed my outlook on it. I am sure that there are people who eat specific diets just because it is a fad and they get conditioned into it by their social circles or influencers they follow, however I am also now quite sure that some of these conditions are very real and people suffer quite a lot because of it (and not necessarily in a physical way but through a very high psychological burden also).

I can tell you from my personal experience (YMMV etc.) that I was able to eat anything and everything without a single problem whatsoever until my early twenties. I was the type of person to eat a kebab at 4am and then go straight to bed and sleep like a baby, now even thinking of doing something like that makes me feel sick. Some of it might be due to aging, certainly, and the doctors I've spoken to have also suggested that increased level of stress might've had something to do with it (which ties in nicely with the gut-brain link), but still what I experienced is that from a certain point forward I wasn't able to eat most foods anymore without feeling really sick (and this has been diagnosed as being IBS, which is truly just a catch-all for gastroenterologists when they don't know what the fuck is causing you problems). From my experience going forward I don't think that it's triggered by very specific foods or stress by themselves, and I've come to the conclusion that it must've been something systemic that I did that led to this outcome (i.e., eat small amounts of glyphosate every day multiple times a day for years).

I think we should really take better care of ourselves and at least explore these potential risks very carefully before dismissing everything as a social media fad / zoomer thing