Not the OP, but until not that long ago there was a social pressure thing of not "advertising" your relatives' history of psychological problems (mostly suicide or time spent inside a psychiatric ward) to outside members of your family, lest those outside members would think you had the potential of having the same issues, too. This is sort of similar to the "uncle" from your example not being free to post "his full medical and psychological history online", I mean, had he done that his family would have certainly retaliated by telling him to remove that information from public knowledge.

Btw, I live in Eastern Europe so I'm talking about stuff I've experienced here, maybe in the States or in Western Europe this behavior changed a long time ago and not only recently.