Any history without some bibliography or source citations is just entertainment. My own family history project utilizes an application that handled this very well. Other applications caught up with the idea, but many, probably most, family historians are pretty casual about what they use and post online.
I did the bulk of my research before the World Wide Web with snail mail and real libraries with books and microfilm readers. I can do the work of a day in minutes now with digitized records.
I corresponded with one man who claimed an ancestor was Native American. When I asked him to support his conclusion he came up with a name match in the 1700s and "that's enough for me!" But not for me. If I'm not certain about something I say so in my research.
I hear you. When I started the web was available but I quickly learned that there's only so much that is available on line and one needs to contact historical societies, professional and religious institutions, libraries of record, sometimes businesses, cemetery offices, schools, etc. to find the hidden gems. On several occasions I hired a researcher to look in places I couldn't access (e.g. L. of VA) and search materials I wouldn't necessarily know about. That paid off every time. I also have quite a collection of things I found by writing and telephoning and, while there were small fees involved, that too paid off. So the old tried and true methods are still in play and, I'd bet, will be for some time to come. Imagine what all those old libraries in the big cities of the original thirteen colonies have that hasn't been digitized and likely won't be (who has the money and time for that ?).
As to my tree on Ancestry, I tagged all their on-line records but I didn't scan every document I have and post such as that would have been way too much time and effort (after all, I know what I've got and it's my tree). However, I often did compose notes ("stories" in their vernacular) explaining things and I always did that if something was questionable. So, there won't always be documentation available on Ancestry even if something is "proven" but I do think that any real researcher will have as much as is available and one can usually see that and use it as some measure of how reliable another person's tree might be.
I also tried to communicate with anybody whose tree seemed rich and who might be related or have info such as mine they might share. I found that most real researchers would answer and be willing to share while the amateurs rarely even answered and, if they did, didn't really have anything intelligent to say. I got in touch with a number of 'lost' cousins that way and that proved to be probably the biggest benefit I got from Ancestry membership.
And regarding sources, the old folks were often just as guilty about repeating a good story without any proof (other than so-and-so said) so one has to be careful about things published in, for example, histories of towns, counties, churches, and such. While often rich sources, they can be just plain wrong too. In a perfect world one needs two or three primary sources that agree to feel pretty certain about a fact.
So that's a very long way to say that I think you are quite right that without sources it's just "entertainment" or, perhaps worse, journalism.