Well, the Queen came out in favor of gays marrying, so we're down to Sharia, and I'm not really certain they Royals are on the right side of that issue, either.
Maybe if enough royals engage in gay marriage we can get rid of the line.
She doesn’t come for or against anything. She signs what her “government” hands her, and reads the speeches they hand her. She reigns, not rules.
She did nothing of the kind. She signed the royal assent to an act of parliament legalising gay marriage. She had no option but to do so, since the royal assent is the last formal stage in the passage of any statute; and it's the monarch's constitutional duty to sign, whatever his or her private views might be on the matter. Assent doesn't mean approval.