I just stated that Button scored more points than Hamilton over their 3 years as team mates which is a fact but yes it's also a fact that Hamilton beat Button in 2 out 3 seasons (but by a narrow margin). I didn't say it means that Button is the better driver (and I don't think he is) but it shows that he compared pretty well to Hamilton with the same machinery. It's a stat that's been mentioned by F1 pundits many times before and is hardly irrelevant. I don't really get the football analogy as you can't really compare teams with different players and managers across different seasons.
Button could get found out by Alonso just like Massa and Raikkonen did. Personally I expect him to compare better than them but I'll still be surprised if he outscores Alonso. Button fully deserves his place in the team and without him McClaren's last 2 seasons could have been even worse.