Uninstalling software is not just about deleting files. In many cases registry entries need to be removed or altered, dlls and other bits and pieces need to be removed or unregistered.
Generally if an install took a while, uninstall will take a while too.
Games are stupidly simple - pretty much every game I have played will work if you copy the game folder to a different computer since during install all it does is copy the files [which takes time since most games are 10GB these days] and make a few shortcuts.