I don't see it as an important distinction. In the end, it's a game that can only be played on one platform.
It's the difference between not getting something you weren't expecting to get, and not getting something you were expecting to get.
Fans of the franchise expecting to play the game bought their console platform expecting to continue it. They have now been told they won't have that option and will have to buy a £300 console to play the game. This is very different to not getting to play Sunshine Overdrive or No Man's Sky which were revealed as exclusive and set everyone's expectations.
The level of emotional response comes from how much these fans were invested in the franchise, which goes to show people really liked where it was going. The developers choosing MS's money instead of the fan's money and loyalty as they see it incites a sense of betrayal.
Expecting people to be unemotional is failing to understand human nature, while equating the loss of an expected franchise to new IPs announced as exclusive is failing to understand the very clear difference between the two.
There are a lot of exclusives I'd like to play, but can't because I don't have the right platform. Lots of Sony and Nintendo exclusives, and some PC ones.
But you know you won't play those games when you buy your console. When you buy a console, you also expect to get access to Madden/FIFA, COD, AC, and other significant multiplatform titles with a history of being available to all platforms. If you buy a console with that expectation and then find that games are being withheld from it, you are faced with a different prospect.
In fact, I'd go so far that this would, if taken further, lead to anticompetitive laws. Let's imagine MS secured exclusivity for those previous all-platform games. There'd be a legal case for anticompetitive behaviour.
I'll ask here as well - how many times in gaming history has a previously multiplatform title with good precedent (let's say three iterations) become exclusive for business reasons and not creative or the natural death of a platform? I don't recall any, but maybe there have been?