Meghan said they got married, the two of them, and the Archbishop was present. In her mind and heart they did hence the word marriage. Nothing wrong with that. She did not expect everyone to focus on the legal aspect
Here’s what Meghan actually said:
…even at our wedding, you know, three days before our wedding, we got married . . .No one knows that. But we called the Archbishop, and we just said, ‘Look, this thing, this spectacle is for the world, but we want our union between us’. So, like, the vows that we have framed in our room are just the two of us in our backyard with the Archbishop of Canterbury… Just the three of us.
So your interpretation entirely relies on you reading words in that don’t exist in that discussion (that Meghan meant that she was married in her “heart and mind” and she did not expect people to focus on the legal aspect). None of which you can know, and which Meghan certainly didn’t say. You’ve had to interpret her words in that way to make them fit the interpretation that you want them to bear - that’s called bias.