Stallion Free
Cock Encumbered
Steam is odd, in that it makes declarations that people don't play X genre, lets a game on the service, gets proven they were talking bollocks and the floodgates open. They did it with shumps (Jamestown broke that barrier), they did it with visual novels (Analogue) and now they're doing it with pinball games. Be patent. I wouldn't be too surprised if Farsight or Microsoft bungled something, but Valve can be a bit of blockade to new games (hence Greenlight).
Did they really make those declarations or did people put those words in their mouths when they couldn't find anything from that genre on the store?