Microsoft was intentionally vague when talking to the EU, but if I remember correctly, they said multiple things.
One thing they said was that they wouldn't have the incentive to foreclose it's rivals of Zenimax/Bethesda games. That can be read 2 ways, do they mean partial foreclosure, or entire foreclosure? Partial is so murky and vague and could mean any number of things. Where as entire foreclosure is definitive; taking all past/present/future games off competing rivals storefronts.
Microsoft said they had no incentive to do that. I can't find the document, but I don't think they specified, again, they were intentionally vague.
When asked what incentive they would need to engage in partial or complete foreclosure, Microsoft gave an answer along the lines of, a significant percentage of new users coming into the Xbox ecosystem as a result of the foreclosure would need to occur for it to make sense.
I think later on when asked about their business strategy in regards to the acquistion, Microsoft said they'd evaluate on a case by case basis what to do with future titles, but I can't remember the document all that well.
(If someone could link me the actual document where all this information is, that'd be cool, not a news story about the EU being misled)
All this to say, I get why people are bringing up the incentive thing, but it was vague and wasn't 100% clear that they weren't going to go for a selective exclusivity strategy going forward.