Because it helps perpetuate that America are the centre of the universe and anything outside of America doesn't count. Sony won November but XB1 won NPD. So, because America are perceived as the centre of the universe, people believe the XB1 closed the gap. It was the reason all through last gen many people on other websites couldn't understand how the PS3 was catching up even though it was getting outsold by the centre of the universe.
"I don't know if it's just me but saying "well the PS4 IS still easily winning worldwide" sounds like damage control when surely it should be the other way around where the statement of "well we won in x region" should be damage control.."
That is just an indication of the level of brainwashing going on. Those who buy into it NEED to buy into it, those who see the bigger picture don't NEED to state the obvious ... We just assume more people are inteligent enough to comprehend such a simple concept.
The PS5 Exists.
