Thread:1ofthe4rocketbros/@comment-24716159-20140513154536/@comment-24740634-20140513203747

Because the page is specifically for Mega Evolutions that do not exist outside of Z/O in the same way that there are pages for moves and species of Pokémon that follow the same trend. Every other Mega Evolution that exists and was introduced in the main series of games is also in Z/O, therefore it is unnecessary to include a specific section for each of them when they can be accessed on bulbapedia or Serebii.

It would be simpler to include a note at the top explaining that every mega evolution that exists in the main series is also in Z/O and then provide a link to this page http://bulbapedia.bulbagarden.net/wiki/Mega_Evolution.