First off, I'm not the one viewing those games through a "seperate" lens... you and others who seem to find international football irrelevant when compared to club football are. The point about sample size is a valid one, but let's say Messi particpates in 3 World Cups (discounting 2006 because he wasn't a starter, so let's assume he plays at the next one, when he'll be 30-31) and he fails to do anything of note, could that still be considered an insignificant sample size?
Also, how is focusing on those two games in any way different to all the various "Player x's record in Finals" or "Player y's record against top teams" permutations? Those usually also represent only a fairly limited amount of a player's career.
Secondly, how exactly does the insistence on international football as inferior to club football work in Messi's favour here? If the quality were that significantly lower how can he be that significantly worse than at club level? And that's even beside the main point. It's irrelevant whether it's even true or not (for the record, I do believe that club football, especially at the top, is of higher quality than international football, but just like SAF or Wenger's shop talk about this matter it has to be taken with a grain of salt) -- the point here is that international football represents a different challenge which can help us understand exactly how good/great a player is on an individual level, by taking them outside of their comfort zone (mostly anyway, there are always situations like the current Spain or German NTs where the majority of players are part of the same club set-up, but they usually represent a minority, certainly post-Bosman anyway). Again, players are praised to the heavens when they can perform to similar levels for different clubs, in different leagues/countries; so why are so many excuses being made when they fail to reproduce (or in the case of so many current greats, not even come close to) it on an international level?