Pokemon has 8 true colors. Not 10. Dragon/Gold is multicolor, but gets supported like a color on occasion. Colorless, well, I really shouldn't have to be the one to explain that one to you. 8 colors is already a lot, and at times seems like more than they're really willing to seriously keep up with as it is.
Fairy was doomed to its fate pretty much from the word go, whether it's due to lack of variety at the time, the insistence to make it a full color instead of a Special color like Metal and Darkness were before they really got their footing, or any number of gimmicks they tried to go with to justify its existence near the end of its short life.
Believe it or not, recognizing the extreme difficulty involved in introducing (or worse, re-introducing) an additional full color that ought receive direct support (or in Fairy's case, what would be almost exclusively
life support to justify the sunk cost) in every set until the end of time does not mean someone is "supporting Creatures being lazy". If anyone disagreeing with you needs to be "defending the evil billion dollar company" for your worldview to stay above water maybe the problem is with you.
Because what is it that you're trying to say by this? That Pokemon making money just magically means that the game's design is infinitely solvable no matter what stupid things they insist on doing in it? At that point, why stop at Fairy? Make like every deviantart / create a card hack that thinks every type should have its own color and flood the game with them. It's easy for armchair card R&D to say what "should" be happening when they have never once thought about things like set composition and how exactly 1-10 new colors would ever begin to have something resembling a distinct identity. To this unformed creative mind, all that matters is sating a desire to see more of something for the sake of seeing it. To hold back the primal nerd urge to "BWUH" post at the thought of a Clefairy being represented by purple. After all.. erm... Clefairy is not Psychic type you know...