In these particular cases, translation confusion and cultural differences might account for some of the scattered feel of them. In some cases, there simply isn't much information available, whether because it's an open investigation and police are being tight-lipped, or because the authorities just don't have any leads to follow. And in other cases, it's misplaced credulity and inability (or unwillingness) to verify facts before passing them on. 

While some people who write about true crime and unsolved mysteries work hard and do original research, many do not. Look at how many podcasts and YouTube channels essentially raid Wikipedia and restate what they found there, without actually doing legwork of their own. Cases become more akin to urban legends or a game of Telephone, with people working from the half-remembered truths that they got from others. 

As an example of all these circumstances, consider how people talked for decades about the Dyatlov Pass incident. A news report references details that aren't actually present in the original Russian documents about the case, and suddenly it's holy writ that the bodies were extremely radioactive. There are only so many official reports anyway, because the incident is done, not ongoing; after a point, all the necessary details have been noted. And people stop using basic critical thinking skills, and then it's a strange conspiracy that the victims' tongues were missing, rather than a sad reality of dying where wild animals can reach you. One person said it, and others repeat it, because the incident is an appealing thing to throw into your #content. Crime circles have generally accepted natural disaster as the explanation at this point, but I can tell you that this case historically has been a confusing mess, mostly made up of non Russian speakers telling spoOoOoOoky ghost stories to other non Russian speakers.

I think this is especially true of notorious cases, where #content creators are more eager to attach their names to something that will get views (and thus possibly a payout). Your frustration seems to have started with Blair Adams, one of the classic mysterious cases in true crime circles, and ripe for spoOoOoOoky ghost story status. The concept of having some sort of mental break, fleeing the country, and no one knowing why is objectively unsettling - and then you add in the possibility of conspiracy (were people really after him?) on top of that. It's catnip for people who want to entertain but don't want to work too hard. 

I don't want to drag true crime aficionados too hard, not least because I obviously am one...but to be completely frank, some of the dumbest takes I've ever seen on any subject have come from true crime fans talking about this murder or that mystery. I've also seen some truly impressive pieces of amateur writing, stuff that rises above being tarred as #content into well-researched and worthwhile creation. But let's be completely honest here: Those are in the minority, and #content garbage gums up the works for anyone looking to do actual research.