The issue is if Microsoft said the rumours weren't true, well, that'd be a lie. If they said "the rumours aren't true but Sea of Thieves and Hi-Fi Rush are" then that'd be a half lie because we know there's more and it provides it without context. They have been planning this for months now, it was always going to be end of February, they've even brought it forward by weeks which probably means rushing the teams to finalise it.
And Microsoft themselves haven't made a firm decision on some titles.
And then if you address rumours, it starts a dangerous precedent where anyone can be a leaker and "leak" something and get Microsoft to respond, sites and Youtubers are desperate for clicks, constantly responding to rumours will fuel more. I think a lot of responsibility falls on gamers shoulders to not freak out over every single rumour, and also Microsoft's shoulders for not being more secure, they need to start being like Nintendo on leakers.
And hot take maybe but Xbox needs to stop interacting so much with certain portions of the Xbox fanbase after this, the reactions of some of them made me realise why Sony and Nintendo barely interact with their community. These people think Phil is their personal friend and that has led to some quite embarrassing reactions, Lol.