I already explained why this isn't the case though?
While you provided your reasoning, the problem with Fairy is the lack of checks and balances outside. Now that you came in on my post specifically to disagree with my points, I will show you why and how I disagree with each of your posts.
I don't get why people think the Fairy type is so broken personally. It provided a desperately needed nerf to dragons and gave Steel and Poison more offensive presence which was greatly appreciated. They also made Fire types more viable defensively. The types they are effective against are all powerful or have few weaknesses of their own with Dragon,Dark and Fighting now having just three weaknesses each
I agree with all of these points. The type was
needed to be introduced in order to pull the type chart back into order. Those are what the type needed to do.
Where I disagree is the notion that its type matchups are fully balanced. The
lack of weaknesses other than Steel and Poison makes Fairies difficult to take out because those two types are otherwise underwhelming and the pokemon often have to give up a moveslot specifically to check them. The lack of types resisting Fairy has, and especially thanks to their narrow distribution, grants it very powerful offensive synergy with strong coverage types like Ghost and Ground.
The balance issues coming from Fairy comes about from its combination of powerful traits which together combine to create the strongest type in the game, not just any of its parts.
There's not even anything special about Fairy moves. Only two offensive moves are good with a third being decent and the only good status move they have is Geomancy which is an exclusive move.
While they are not anything particularly special about the moves and they are few in number, the type has a very precise list of moves - The type has strong 90+ BP offensive moves on both sides of the spectrum that are readily available to them and lots of special attackers get Fairy coverage in Dazzling Gleam or Moonblast. Their support moves, while few and number and situational, tend to be powerful when used in Doubles.
There's not even that many viable Fairy types with the Tapus being the only really noteworthy ones - and they're a lot more notable and useful for their other type than being Fairy.
The Fairy pokes in OU, namely Mimmikyu, Magerna and the Tapus, benefit greatly from having their Fairy typing because it grants them valuable STAB coverage to threaten out various threats like Garchomp and Tyranitar and their resistances are powerfully utilized to discourage Dragons.
On a second note, note the big boost in viability the pokemon receiving the Fairy type got on the transition to Gen VI. Even if they didn't make it to OU itself, they made at least some headway in the lower tiers. That's a testament to how strong the type really is. And that's even considering that the pokemon who got the type were often really bad beforehand.