I haven't looked at how they're sorted in a while, but I'm guessing becase PS4 and XBO are still going and are paired up against Switch, they don't want a second Nintendo home console there. And if they don't consider WiiU generation 7, they probably wouldn't want to pair it with PS3/360.
At a certain point, the person doing the mainpage will realize the Switch is really in generation 9. Might not be until the PS5 comes out though. Until then VGC will pretend the Wii U never existed.
If it turns out that it won't be able to run most generation 9 games, I'm not sure that would convince them of this.
Last edited by Hiku - on 21 September 2018
Either way, as long as the current consoles are on the front page, and the rest can be found intuitively, the categorizing is not that important.