I don't think they were being bias.
I guess people confuse changes in time and relevance to Bias.
Because during gen 7, even small differences in resolution was blow out as very relevant but after the first few titles on gen 8 it was said that resolution wasn't that important anymore (and peope considered that a change to favor Xbox, while it actually had more to do with after moving to 1080p the resolution was mostly fine anyway and framerate was what mattered), and now they are saying framerate doesn't matter as much because of VRR and the like but again that is because the important thing now is solid 30fps with solid 60fps being a big plus and 120fps being just something consoles really shouldn't be bothering yet.
People need to remember that at least since PS4Pro DF said that their checkerboard upscale was almost as good as native.
So for me sure it could seem as bias for MS, but seems more like they are moving the goalposts because the goals were achieved on what was important so they moved to another metric, and will keep moving as industry changes focus and the previous metric becomes irrelevant because it was already achieved good enough.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
Azzanation: "PS5 wouldn't sold out at launch without scalpers."