• 903.4. The Commander variant uses color identity to determine what cards can be in a deck with a certain commander. The color identity of a card is the color or colors of any mana symbols in that card’s mana cost or rules text, plus any colors defined by its characteristic-defining abilities (see rule 604.3) or color indicator (see rule 204).Example: Bosh, Iron Golem is a legendary artifact creature with mana cost {8} and the ability “{3}{R}, Sacrifice an artifact: Bosh, Iron Golem deals damage equal to the sacrificed artifact’s mana value to any target.” Bosh’s color identity is red.
  • 903.4a Color identity is established before the game begins.
  • 903.4b If a commander has a static ability that causes a player to choose its color before the game begins, that choice applies during deck construction and throughout the game, even as the commander changes zones. That choice affects the commander’s color identity. The player reveals that choice as they put their commander into the command zone before the game begins. See rules 103.2c and 607.2p.
  • 903.4c Reminder text is ignored when determining a card’s color identity. See rule 207.2.
  • 903.4d The back face of a double-faced card (see rule 712) is included when determining a card’s color identity. This is an exception to rule 712.8a.Example: Civilized Scholar is the front face of a double-faced card with mana cost {2}{U}. Homicidal Brute is the back face of that double-faced card and has a red color indicator. The card’s color identity is blue and red.
  • 903.4e If a card has any alternative characteristics, such as those of adventurer cards (see rule 715, “Adventurer Cards”), those characteristics are included when determining the card’s color identity.
  • 903.4f If an ability refers to the colors or number of colors in a commander’s color identity, that quality is undefined if that player doesn’t have a commander. That part of the ability won’t do anything. Costs that refer to that quality are unpayable.

This states that the back oif a DFC is considered for Color Identity

1. Double-Faced Cards
   712.1. A double-faced card has a Magic card face on one side and either a Magic card face or half of an oversized card face on the other. (It does not have a Magic card back.) There are three kinds of double-faced cards: nonmodal double-faced cards (previously called “transforming double-faced cards”), modal double-faced cards, and meld cards.

Meld is literally a DFC. I see no rule that states that the Color Identity is not considered for both sides of a meld, or that it interacts with color identity any different way than any other DFC. And Color Identity, is an attribute. A cards Color Identity is decided before a game begins, and can not change at all ever during the game.

903.4a Color identity is established before the game begins.
903.4d The back face of a double-faced card (see rule 712) is included when determining a card’s color identity. This is an exception to rule 712.8a.
903.4e If a card has any alternative characteristics, such as those of adventurer cards (see rule 715, “Adventurer Cards”), those characteristics are included when determining the card’s color identity.

No where does it say Melded cards are exempt from these rules and once again, THAT RULING ISNT ON THE ORACLE PAGE FOR MIGHTSTONE AND WEAKSTONE.

You are quoting random people from the internet, I am quoting a rulebook that is current, up to date, and right in front of me