The Steam Workshop has constantly been subject to attacks from Dangerous Malware due to Valve's negligence of their moderation around The Steam Workshop. 

Some notable examples of this include: Mecha Chameleon (Never personally played it but I heard about it's malware attacks). 

People Playground, there have been three consecutive Malware Attacks by an unknown, Malicious Group, with no punishment for them. 

I believe this has been caused by Valve's Negligence to moderate the Steam Workshop, letting bad actors manipulate, or exploit the Workshop to upload malicious Content to it. 

EDIT: 

A common defense of Zooi I see being slung around is "But Steam's TOS says all accountability falls upon the  downloader", that is true for a mod that comes out of nowhere and is doing malicious acts, but for a virus which for example, auto-updates your mods, it is not. 

The People Playground's viruses main mechanism to infect players wasn't getting them to download a random mod, but infecting mods people had already downloaded, Steam's lack of a manual updating feature directly contributing to this is what I believe caused this. 

There is no "As-is" Legal framework applies to already-downloaded content to my knowledge. 

Our proposed change is force the downloader to manually update their mods, so all accountability will be on the user for the update, and not the flawed systems auto-updating them.