This is classic shortermism. Reddit is, in the short term, driving more external users towards creating user accounts while in the long term removing one of the major value funnels for why they would (i.e. the quality of comments, particularly in certain niche communities/about niche topics). This will give them a short term "bump" at the cost of the site's long term relevance (as it falls down Google's search result…
Nothing lasts forever. Reddit is 14 years old. They've had a good run. I think there is a general trend away from user-generated content as a business model, because that content can be a bit salty. Reddit might just be cashing out because the wave they rode has already crested.
Why do we accept that such a short-lived company (less than one human generation) is "a good run", just because it's software? If Tesla turned into a "classic pump and dump scheme", nobody would say "Well, Tesla is 16 years old. They've had a good run."