I don't think there are victims per-se, just people that have willingly enabled a mechanism to come into being that they profit from at the expense of general freedom in computing. That Apple and Google would throw their weight around was a foregone conclusion and if MS manages to make it so that installing software on PCs can only happen through their app store (which is a fair chance, all the indicators are pointing towards them shooting for this at some point) they definitely will not shrink away from that.

Also note that through their control of GitHub they could shut down 90%+ of of the FOSS movement out there with the click of a mouse.