I honestly don't really see it that way.
As much as it's hard to realize during this point of the year, the regular season stops mattering when you make the playoffs. This is all to set up the playoffs. The entire season happens in order for each team to try to win the cup, not win a single game, not win against a specific player, not win out against a specific team in the regular season series.
And in the playoffs, which this is all simply a lead up to, MSL helped push the Rangers to the finals, and Callahan went pointless while his team got swept. Now, that's the past, yes. But frankly, so are the last two Tampa games. Until this year's playoffs, that's what the Rangers did in the post-season, and that's what the lightning did. One team fell just a tad short, and is back at it right now, and the other barely put up a fight as is thinking "well, this year we'll pull it off" just like they did last year.
I don't see Callahan scoring a few goals, some of which were pretty much tap-ins thanks to Stamkos, as rubbing anyone's nose in anything. His success this season in two games against the Rangers doesn't even begin to come close to the success that the Rangers and MSL had last year toward the actual end goal of all of this, and the spectacular failure that Callahan and his team had toward that goal.
If those were playoff games, god forbid, then, yes, people better perk up and find a way to get pissed off about it. But honestly, it's not that big a deal in my eyes that he's done well in two regular season games against the Rangers, especially considering that he's playing with Stamkos. Stammer and his line mates are going to score if you play TB enough. Worry about the Xs and Os of analyzing and preventing that, don't get all emotional about an ex-Ranger being the last one to touch the puck before it goes in during the regular season.