It’s not as game-breaking as you make it out to be. It doesn’t automatically give access to ALL enviromentally-protected missions. You must find and join a multiplayer game for each individual mission you want to add. Hardly practical. It was also intended to give more freedom/incentive for multiplayer.
Having said this, I am disabling it (see below). Changed in v.95 
Idea
That’s ok. I only created an icon for use in the multiplayer browser.
These are not distinct mission types.
This can’t be easily changed. Environmental restrictions are not saved as part of the mission. The same thing happens everywhere in the game: squadron assignments, dares, cups, weekly, etc. You don’t need to have the equipment to fly the mission.
That would be a much more practical solution. Done.
It servers a purpose. Knowing which version screenshots/videos are taken from helps a lot with debugging.
No
No