Maybe Wii and HD consoles should be in "different groups," too? Maybe that's where these differences of opinion are coming from. Maybe to some people, wishing Xenoblade had the graphical prowess of something outside its "group" is "asinine."
Taken to extremes, of could, we could place every individual kind of hardware into its own group and then never have to think about comparing anything. I'm not even so sure this is a bad thing.
The issue is that the border lines sometimes seem to be drawn strangely. In this case, it's saying that Wii graphics are unacceptable because of what other consoles can do, yet not saying that those consoles themselves are unacceptable because of what PC's can do. It makes it sound like a post-facto rationalization, wherein one claims to want the best graphics, but are suspiciously willing to settle on less-than-best as long as this choice is inclusive of certain companies' hardware and not others'. Another example would be people who claim that Wii graphics are "good enough" and anything else is just pointlessly going past diminishing returns, while bristling at the suggestion that the industry should never have advanced past the SNES or something. Their preferences oddly single out the Wii as the perfect console, which is so coincidental that it seems like what's really happening is they're inventing reasons to prefer the thing.
Around here it seems to be the utmost sin to claim to like something for "objective" reasons which instead seem to point to preferences for certain companies or IP's or other "irrelevant" factors.