>>714791174I'm sure their reasoning was because it didn't make sense anymore taking up developer time and money. I don't agree but I do agree that there's issues with security now. If you mean SM2, they started off making a MW2 (2009) mod altough that game never officially had any modtools released and they don't support it. But then they changed it to a newer engine and didn't require people to verify their games leading them to pirate the game essentially and they just shut it down but they a history of doing this.
tl;dr modding is safe (legal wise) on the officially mod supported CoDs: 1, 2, 4, 5, BO1 and BO3
there is a spectrum of modding though and most of these that get C&D try to mod the .exe of unsupported games.
Security wise all of these games still aren't safe. Some COD games just allow you to drop in a new .dll and it'll just execute it with no sandbox LOL. I think Wolfenstein ET also does or did this, but Quake had a QVM. Some other CoD games require more sophisticated exploits but they still exist and games like CoD4 actively use them to install their mod CoD4X.