Very valuable contributions, well done.
I'm not getting why you think that's so far fetched. Here's how these things tend to go: a proposal gets made by non-technical people (sales, marketing, relationship managers) representing the companies in question. They agree to look into it, pending a review by their subject matter experts to check if the proposal will be feasible in terms of the company policies and standards. There will be a minimum set of criteria that Microsoft will have (and they're MS, so these criteria will be lengthy, and specific, and if you don't meet the requirements, you generally have one of two options: either bring your product up to the minimum requirements they accept, or no deal). The relevant due diligence (including a review of security standards) is carried out and is found not to meet MS's requirements. (Interestingly, a refusal to answer can also count as not meeting requirements.) Ultimately, MS refuse the deal on that basis. Gamers and their desires don't feature in the decision, but they end up viewing the result as an intentional slight on them instead of a normal run of the mill unsuccessful assessment that happens every day in large corporations.
Again, I'm not saying this is how it happened. I just think it's better to discuss the complexities behind these things instead of the "herp derp, MS hate customers" stuff that gets trotted out. Clearly a lot of people have no idea.
