It can be a useful tool for writing and discovering things that have story elements that you can like. On the flipside, there is a tendency to believe that a story can be broken down into parts and can be categorized, and that these categorizations make something 'good' or not. People obsess over these story components rather than enjoying the story in and of itself.
Also, some of the userbase has a tendency to be obnoxious in this regard. Trying to label this behavior as
REDDIT is an oversimplification.
Stories are not legos but many who use TVtropes have this tendency to look at stories and see these interchangeable parts. Or that 'writing a good story' is avoiding certain story elements. That and some used to think fictional story elements could be applied to real life back when the (embarrassing) forums were still a thing.
Basically paraphrasing this:
https://www.youtube.com/watch?v=uQsPo6L9m-A