It is by no means presented as a fact. It's a "here's what 5000 people voted as the the best franchises/games ever" kind of survey and nothing more. They didn't try to hide it.

We have no idea who voted for these games. As one of the users here (Lewis something) once said, someone's mom can be considered a hardcoere gamer if she plays a game like tetris constantly and passionately. As someone who has played Just Dance and a few thousand other games, I can tell you that it's one of the most fun times I've had playing a game with friends. I wouldn't vote for it as the best ever, but if someone did, I'd have no problem with that.

And it's not just casuals who play these games. People who play video game but don't spend time on forum are as just as much gamers as we are. The difference is that they don't express their opinions online like we do. That gives the false impression that people don't find games like COD, Fifa, and to some extent Minecraft fun. I'm not saying that sales = quality. I'm saying that this list is fine for what it is. It not based on quality or on a reviewer's opnion, but on the public considers as the best. For them best = a game they have fun playing, hence the list being based mostly on popularity.

Also, out of curiosity, have you actually played Just Dance?  

Think of the grand scope of the questions we have here on VGC. And we're having at most a few hundred votes, most of which are bots.

Yet we all love the polls.

But we arent putting our answers in world record books. Something about the poll for "best game ever" being asked by the actual guiness book of world records having such a small sample, despite being about every genre and platform seems like a bad idea.

I think you're giving that book a bit too much credit. It's not the Oxford Dictionary.