Yeah it may be legitimate, but is this a fun list to fly against? I don't think so. It's a waste of time and taxing my patience.
This is a point that keeps coming up. Some people have this idea that it is somehow the opponent's responsibility to make sure you have fun, which it is not. That is not to say that players should not try to foster a friendly environment free of drama and hostility (to which end a sore loser complaining about his opponent's supposed lack of sportsmanship certainly does not contribute), but players are free to build and play lists as they desire within the game's rules.
Consider some other builds that have been mentioned: dual Falcons, Falcon fortresses, Lambda Fortresses, etc. Or even the Rebel Convoy build, 2x y-wing with ion and 2x Outer Rim Smuggler, which had some success last year and lots of people were talking about how happy they were to see nontraditional builds performing well. These builds are top candidates for making the match "not fun" for many opponents. Should they be banned too? How exactly do you phrase a ban on "unfun" builds or tactics?
And again, this tactic is not even an issue. It is not common in the tournament scene and most players don't seem to even consider it an effective tactic. The only situation where an idea like "this game is really good, except X ruins it. Let's ban X" is even a remotely valid concept would be if there really was one specific thing that was obviously "ruining" the game. For those familiar, consider the video game Super Smash Bros, a game series which has all sorts of design issues but the community liked the game so much that they managed to form a consensus and ban a large portion of the game's content to shape it into something that still manages to support a large competitive scene years after its release. X-wing is not even close to this kind of situation.