Yes, MC will not move files unless you tell it to. If you do want to move the file, you can use Right Click -> Library Tools -> Rename, Move, & Copy Files. More info here:
http://wiki.jriver.com/index.php/Moving_FilesYou can right click and edit tag info. In a category view, just make sure Media Sub Type is a column showing (right click on the header and check it, if it is not). Then right click on the tag (or several selected to do more than one at once) -> Rename.
You can also just right click a file (or files) -> Library Tools -> Find and Replace -> Click: Check None -> Check: Media Sub Type. Find: TV Show. Replace: Movie.
There is a dragging tagging method also called Tree Tagging:
http://wiki.jriver.com/index.php/Tree_Tagging I do not use it often though.
Another easy way to change several tags at once is to Enable Pane Tagging in a Pane View. Add Media Sub Type to one of the Categories panes (right click on the header of any pane -> Customize View -> Add -> Sect Field: Media Sub Type). Then select the files you wish to tag down below, and check the new tag in the Media Sub Type pane. You will get a pop up explaining Pane Tagging, click Enable Pane Tagging Now. You now just batch retagged all the selected files for a new Media Sub Type. More info here:
http://wiki.jriver.com/index.php/Tagging_ModeOne of the beauties of MC is that there are several ways to skin a cat. Just find what works best and easiest for you.