Funny enough, there will be games that you can't play on your Xbox but you don't see Xbox gamers whine about it...why? Cuz it's a PC game...but I definitely see the other way around. PC has millions of games that console players just can't play over the lifetime of the industry but PC gamers pull a fit when MS says they are committing to them (and even alludes to making PC centric games) but that their big exclusives aren't coming to PC day and date.
There is a very specific difference there. The "Cuz it's a PC game" argument doesn't hold true for anything other than your generalised view of what a "PC game" is - likely strategy style games or things that have traditionally been PC only due to input or feature sets not available on consoles at that time. There is countless begging from console owners in threads for titles that only have a PC announcement at a given time, we saw it with Civ BE, Xcom 2, FireWatch, Dirt Rally, Shovel Knight, Valkyria Chronicles (even though already on PS3) etc etc.
Equally there is a sizeable amount of the same regarding other games that are console only at a given time, since generally there is no reason for a game to be withheld or not possible on a PC - unless there is an exclusivity / development agreement in place to withhold it. Most commonly though, there may be development or financial constraints for a particular developer leading to the PC versions coming later on, which still sees begging directly to the developer, since there is no dedicated platform holder there make their voice heard
The big issue here is Microsoft claim to be "unifying" PC gaming and Xbox gaming, when in reality that is not what they are doing at all. A unified ecosystem should have functionally feasible content on both platforms, but selectively Microsoft do not do this in order to prop up the Xbox console. By all means, in this interview stating that the games were planned ahead of the decision, that is fine if true. But for other games they should be available across both unless it is not functionally possible. What games are not "suitable" for the PC platform?
Deciding what games are "suitable" for each platform is a bad precedent particularly for the PC, when there is no functional reason to prevent games going to PC unless there is a cost issue and tiny market size on PC making such a move unlikely to be justifiable to develop. Fundamentally, that has been a great part of PC gaming and why it is popular now. Microsoft claim commitment to it, but are doing it in the most lackadaisical way
The fact of the matter is that this isn't about "PC gaming" being unified (as it ignores the entirety of developers / other store fronts and their own communities etc). This is about Microsoft's version of PC gaming (Xbox on Windows) from its own store, being unified only in a partial manner with that of the Xbox console gaming. Their "dedication" to the platform is only a little more than it has been in the past (or similar to that of GFWL which promised the same things, only via a gaming store front dedicated to it).
I think it is a combination of these things that irks people