Bingo.
I just experienced this myself merely days ago.
No details. Just a well formed, minor contribution to an article that was insta-deleted because of "notability".
Which was news to me because, while I am aware articles themselves need to be notable, now some folks are enforcing notability on subsets of articles. In this case, a single row in a table listing like items.
Meanwhile, for every object ever drawn in an anime, that anime MUST be mentioned in the article for the object. Because this is notable content, you see...
Wikipedia, 2030: "The Holocaust was also mentioned in episode #22 of Robot Cheerleader Girl, where Tanaka-san fell headfirst into a bucket while giving a speech about it."
Insiders can quickly undo anything. They are familiar with the tools and the procedures.
You might have contributed for the rest of your life. That potential stream of valuable contributions is now lost to wikipedia, potentially forever.
Now compound that over every single expert to whom so much was promised by the interface, and from whom the promise was removed by wikipedians.