I know you like saying this, but is there any evidence whatsoever that there were Gold complaints about non-Golds (travelling with Golds) sitting in Gold seats, therefore restricting the choice of Gold seats?

I somehow doubt it. There were always Gold CE seats available up until OLCI, even on busy business routes.

Even if this is the reasoning behind it, they have screwed it majorly. Now there are no Gold seats on the UD. There are fewer Gold seats in CE, and there are no Gold seats on busy business routes like Moscow. So they have actually achieved the opposite of what you suggest might have been behind this.