Sounds like it's time you modded a different engine then, doesn't it?
I don't mod or edit games which require Steam because of the very reasons I listed. It's a shame Valve had to ruin modding for its games in the name of greed and control.
You will be safe from Valve's mind control then...
I said nothing about mind control. However, Steam does give Valve unprecedented control over and greatly limits how its customers play and otherwise use its games. That's not paranoia. Any rational person who has studied how Steam works and has read the Steam EULA would come to the same conclusion.