I purposefully choose not to install games through Galaxy, because I just want to play the games. I don't want to fuss with a front-end, but Galaxy will start itself up and just decide its going to run, when I start up games I specifically chose to use the offline installers for.

There are two types of offline installers. One with Galaxy included and one without. Seems like you downloaded the ones with Galaxy.

I'm only seeing the one offline installer though.