My guess is advertising CPI is much higher for authenticated traffic, and crippling the anonymous experience is found to maximize authenticated traffic. But no

My guess is advertising CPI is much higher for authenticated traffic, and crippling the anonymous experience is found to maximize authenticated traffic. But now I'm speculating on why the developers of the site do what they do. In my previous comment, I was speculating on why users of the site do what they do. While the former obviously influences the latter, motives and goals are quite distinct for each.