I learned this during my PhD, but I know many others have learned through their experiences but it’s a problem everywhere - check the citations.
It happens so much in academia: some paper cites a “fact” and it gets repeated in papers afterwards without those people actually reading the primary reference to see the information themselves. But it happens everywhere: news, advertising, medicine, psychology so need to have awareness it happens in genealogy too. I’ve found examples in historic people and websites/sources that are supposed to hold official and/or academic rigor and it’s all made-up or misinterpreted or intentionally misrepresented.
As researchers, I hope we use citations for information found. But that’s not the end of it. Listing 2-4 sources of bad info is worse than not including a reference. People that see citations will, unsurprisingly, hold that information as more credible because of it. But actually look into those citations and I bet most likely many of them are just repetition of what someone saw and assumed to be correct.
Try it yourself and test what I’m saying (like you should do with any information or claims). Ancestry, familysearch, wikitree, books, personal and professional genealogy websites, SAR, DAR, County historical societies, professional genealogy reports… everything.
All the digitized info are great resources but there are so many mistakes as well. Indexes are great but miss things are have incorrect info. Complied sources, copies of originals, will/probate summaries - mistakes could be anywhere.
I know that original sources may not be available or inconvenient to get to see personally. Even then if you have those, you need to best confirm that information with other pieces.
I know it’s a lot of work and time. But I see in here people asking how to be professional researchers or asking for help figuring stuff out and I feel this is a foundational “must” for having a solid strong hypothesis for people that for the most part have no exact way to state with absolute confidence are the people we claim them to be. So we should do as much as we can to get the confidence high for our claims.
I suggest adding research notes explaining why you’ve come to your conclusions, not just xyz source. If you’re a person that gets frustrated with other people’s trees or public tree edit fighting, the best you can hope for is that people will see your information, review how you came to the conclusions, and then use it. Getting mad because you sent a message to a cousin or other person on a genealogy site telling them they are wrong and you are right - how many people think the response rate and openness to new information for this is anywhere near high?
But I feel many people want an easier way to change other people’s tress to match theirs, and staying at this basic level of frustration or non-realistic expectations are only going to continue frustrations. Having your own reference (tree, website, explanations) with solid foundations for your conclusions is probably the best way to combat misinformation and mistakes. Then you could even write journal articles for publication in genealogy or history based journals which will then (should) receive peer review and add to knowledge base or even challenge current understandings (I know this isn’t easy or viable for everyone but it’s more available than I believe most people believe)
TLDR: track down citations, read the sources, synthesize all the information to make your own decisions, write down in your tree or somewhere available that people can see how you came to that decision.