Two words.
loving.
BULLstuff.
forget off Valve, you useless cunts. Was I going to buy the game? Probably not. Would I like the option to be able to buy the game? Yes
Censorship is ruining this loving society. forget every single Politically Correct starfish who do stuff like this. I can't even loving playing Saint's Row or South Park without it getting loving censored because our Government is afraid of brown town probes (aka slightly more dangerous carrots).
The game got bad PR by the press and if steam sold it the press might go after them, bad press for steam could drive away potential customers, which would lead to fewer sales, which would lead to other companies selling their products on destruction platforms like Gog and Origin which would be bad for Valve. They could care less what the game is about, they are just protecting their interests.
Same reason how Gabe Newell rolls out onto the stage and blabs about how evil Windows 8 is, and how he has the interests of pc gaming at heart, and how evil consoles are, and bashing companies like EA. Valid concerns, but these statements for ulterior motives. Ones that make them money.
If valve truly stood against this game, there wouldn't be blood in half life 2, TF2 would have been a kid friendly Pixar rip off, and you wouldn't have been able to gib enemies in Half Life 1. Nor would they have sold games like Postal and GTA which have all received flak at some point.