Sorry I missed this post -- it's a good one.
The only thing I'd suggest here is that third-party APIs have been tolerated in the past because even though they don't produce direct revenue, they tend to increase valuation for a company that goes/is public because they bolster user engagement numbers. Twitter jacked up their prices intentionally to kill the API, because it's now a privately held company that is very reliant upon ads.
As Reddit looks to go Public, alienating a large swathe of their userbase has the real potential the devalue their IPO, which is why it's all the more confounding to me that they moved forward with this.