First thing I thought of when I saw the title was "since when does Steam have wallpapers?".

The article is at the least titled misleadingly and an attempt to sell fear.

The malicious wallpapers, which use "Wallpaper Engine" are also published through Steam Workshop. It's still a Steam problem.

Centipedes? In my waifu?!

Sexual arousal also tends to inhibit rational thought. I don't mean that in a snarky or sarcastic way, I mean that it is a biological process that has been well-studied and well-established [1]. This has obvious uses for scamming people and doing other things that their executive function might normally catch and prevent.

This is also why sexual imagery should generally be kept out of public spaces, not because of "puritanism" but because it just generally isn't a good idea to go around letting bad actors inhibiting people's executive function willy-nilly. That should generally be denied as a tool to bad actors like scammers.

[1]: For instance https://people.duke.edu/~dandan/webfiles/PapersPI/Sexual%20A... - note while the title mentions "sexual decision making" it also covers some 'bad decisions' that aren't particularly sexual on their own.