I worked with this extension a little more and found out a few things. This extension VASTLY underestimates the volume of users and content that needs to be deleted. I had thousands of accounts created by a bot, and even more pages in the Wiki. If I selected a couple dozen users the process would successfully complete. Although I had to run the program on the list of users twice to delete all the content.
Unchecking thousands of users to run this extension twice on small groups took forever. Yes, I used the click+shift method to uncheck all the boxes.
After successfully blocking and deleting the content the user names still showed up in the list. Which required me to remember the beginning and ending user name in a list of thousands.