I'll tell you why...
Lots of user (me too) cannot remove Super Cache easily. Super Cache cannot remove itself remnants. One day, I install wp on cpanel and super cache was installed automatically. I tried to uninstall but I couldn't do it :) I was so angry and I decided to add such warning.
it says is that the wp super cache is a bad plugin but no explanation as to why
It is not about its functionality. just about remnants.
childish accusations
You are right. I need to change this warning message.