I'm yet to see any real connection between those guys and valve (game credits or direct mentions from valve)All the info you need about this game:
Think what you will but in my opnion, the most likely explanation for this is because SB worked with many games/devs that have valve as a partner (aka they sell games on Steam) and/or they worked with third party people that organizes steam sales (sales like black voices in gaming, season of pride and antrho festival). Those sales are custom made by a third-party, valve just gives them the platform to organize their own events/sales.
The type of insuferable people that support SB despise/screech at valve:
-like some ex-valve devs:
-and retarded gaming "journalists" (and their friends) like this guy on youtube screeching that valve is too white and too male:
(invidious instance of the video to not give him clicks: https://yewtu.be/watch?v=s9aCwCKgkLo )
So no, I dont think valve worked with them directly. Anyone can claim valve is their partner/client or whatever if you sell your shit on steam lol.
Bro have you looked at the artwork of any recent Valve game, sale event or anything at all?