Super Mario Maker was released 14 years after 9/11, so in this case people aren't expecting Nintendo to be psychic, but it still shouldn't be that big a deal since it's being done to celebrate the anniversary of a game that was released 16 years (minus two days) before 9/11. (And even if it weren't, it still shouldn't be that big of an issue - video games are fun, and having fun shouldn't be considered inherently offensive to survivors of tragic events.)

I'm not saying that those affected by 9/11 should never take offense to anything; I'm just saying that Super Mario Maker shouldn't be that big a deal. :)