1. They are not "reining in" expenses, they are purposely pricing out 3rd-party clients (which probably has the goal to show more ads, not less)
2. The $10M buyout comments was a reasonable comment countering the statement that reddit loses $20M each year by users using Apollo. A comment which was a half-joke, as the audio recording shows clearly. In that case, buying Appolo for $10M would have been a steal and Reddit would have jumped on it. They didn't, their prior statement was probably a lie.
3. There were no suggestions for reasonable optimizations of API calls. Apollo claims they already optimized whenever possible and whenever they were asked for it, and that client was specifically not listed in an earlier discussion about ineffective API usage. Reported measurements confirm that, the official API uses more calls. Regardless, later Reddit made this accusation, showing that they are not truthful in this discussion.
Your pro-reddit position is not reasonable.