All The Tropes uses "Category:{{PAGENAME}}" to identify that a trope, work, or creator is the top part of a hierarchy of pages.
"Category:{{PAGENAME}}" is the format used in the new-page templates.
If we wanted to have {{PAGENAME}} replaced with the name of the page, we would have coded the template to do that. The fact that we did not should tell you something.
I have been replacing "Category:foo" with "Category:{{PAGENAME}}" manually on existing pages every time I see it for years now. I don't appreciate a bot coming in and re-breaking what I've worked to fix.
I have blocked your bot for one day so that it cannot do more of this damage to the wiki. Please fix your bot before running it again.
@Labster @Looney Toons @GethN7 @QuestionableSanity @Derivative @SelfCloak