I am not making this up. I said "silently" protesting. I.E we don't fully believe in the leadership or direction of the club. Prior to Xia - we had years of poor football/results at VP, bad owner, poor managers, poor players which alienated fans. Trust was broken. There is no context to your original post. Most clubs will have big attendance dips if they had the years of decline and experiences that we had.
People were questioning Xia from the outset, then we had not so popular managerial appointments added on top with poor football. It is important to remember we were still one of the highest attended clubs in the championship (over 30k), if not the highest by the time of our return to the top flight. This is always never considered but only that our support is "fickle". Our core support is loyal.
Our attendances rocketed under NSWE and Smith in the championship to over 40k, which showed our attendances can be increased when trust is regained with the wider fan base. IF we had that set up after Lerner, we would have had over 40k in our first championship season imo.
The capacity increase is about finding that sweet spot inbetween 50k-60k imo.