why there is a repair option ?

i just finished a fresh install of the game on my laptop but had a problem and the game wasn't starting when i press launch so i tried the repair option just to to find out that it reinstall the game from the beginning ! so why there is a repair option when all it does is just reinstall the game ?!!!! i can do this manually ! anyone knows how i can stop that repair because now every time i open the launcher it just starts downloading the game i don't want to reinstall the game again !!