Thank you for the comment. This is a great observation and it is true that many of current relationships on System are not comprehensive (i.e. they are not based on a representative sample of overall scientific consensus in that field). Some topics/relationships are more comprehensive than others (e.g. relationship between food fortification and anemia: https://system.com/view/topic-relationship/yQrSS5fcTQs/d9wUM...)
System is still in its infancy. Compare it to early days of Wikipedia. Over time, our goal is improve the depth and breath of knowledge on System through various methods including community engagement and partnership with domain experts.
Meanwhile, if you are interested in exploring a specific topic, please let us know through our slack community (link on the platform) and we will be happy to prioritize them.
Example: I saw there is a relationship between "rural area" and "major depressive disorders", "established by 1 source": https://www.system.com/view/topic-relationship/wdlsYqXAGFc/j...
Is there really just one study about this? What would happen if there was one study saying that there is such a relationship, and one saying there isn't?
To me it seems that this kind of system leads to a weird simplified spaghetti view of the world, which at best might be an ok topic explorer, but at worst almost like a conspiracy theory automator (following the threads of more or less representative studies of things being "related").