How do you quickly remove underscores from folder names?

Bulk Rename Utility is a lightweight program that can accomplish this. In addition to supporting the use of regular expressions, it also has features to accomplish what you want in a more user-friendly way.

To use Bulk Rename Utility, install and start the program (there is also a portable version if you don't want to install it), and navigate to the folder that contains the folders you want to rename. Then, select all of the folders you want to rename.

In order to replace all underscores with spaces, in the Repl. (3) section at the bottom, type an underscore in the Replace box and a space in the With box.

In order to change the names to Title Case like in your example, use the Case (4) section. Choose Title from the drop-down menu.

Look at the names in the New Name column and make sure that they are what you want. When you are done, click Rename in the lower-right corner.