To look at the other half of your comment, I think it's more or less indisputable that the social interaction of non-consensual participants here adds negative value to the acquisition and retention of active users. They're not doing any of that work, and they're taking time and mental energy away from many of the people who want to.

It seems like this would also be true of any competitor that tried to implement an involuntary system. They would have bid-bots, and fight about bid-bots, and we could keep making ourselves better while they did.