Earlier quoted context omitted.
If you go into that thread there are people begging Selig to charge them 4x what Apollo Ultra costs. And they're begging him to charge it to everyone all the time. This can't just be laid on the feet of faceless bean counters or old men in the executive suite.
40% of reddit posts are marked NSFW. All those won't be able to be accessed from the API. And those NSFW posts are far from just porn. It's frequently news (especially related to war), the "vice" subreddits (cigars, guns), mental health subreddits, ect. Also, 4x of Apollo Ultra is probably not enough. After the Appstore takes its cut and the dev pays himself, you're not left with enough money to pay for the API acces…
And for the longest time, many subs based their flairs around the NSFW tag combined with some CSS hacks, especially for subs based around TV shows wanting to add spoiler warnings. Some subs never bothered to update to the new system and still use this.