IdleMaster has nothing to do with installing games or uninstalling games and it has no effect on whether steam thinks games are installed. IE this has nothing to do with idlemaster.

Idlemaster does one thing - it tells steam a game is being played to get the cards, steam doesn't care if the game is installed, it still drops the cards, game installation is irrelevant to this process.

It shows in your "READY TO PLAY" as installed and I am having trouble removing them from that list. I get that they are not installed but they are still showing up in that list and on my "RECENT GAMES" list which is a bit annoying and is cluttering up lists I use regularly.

If you right click on the game you can remove them from whatever list they are clogging up, but they still show on the Recent Games list and I don't know what Hiding a game involves.