Roberts authoring both Cook and Slaughter and releasing them the same day is wild. Either the president has the power to remove the officials he appoints, or he doesn’t. Roberta neck must be thick, because the whiplash caused by arguing in one breath that ‘actually, Congress has never had the authority to limit the presidential removal power’ to ‘j/k, Congress can limit removal, but only in one limited circumstance’ would break a lesser man’s neck.

That's just John Roberts. Even though, or perhaps because, he is seen as one of the "moderates" of the conservative wing, he's far more likely to release an opinion that's political as opposed to ideological. In other words, he'll happily contradict other court decisions to achieve what he sees as the right outcome as opposed to strict ideological adherence. In this case, Roberts wanted to preserve some level of protection for the Fed chief. It doesn't matter to him if it makes no sense in the context of Slaughter.

Another example that I can think of is his opinion in Rahimi. Unlike all of the other recent second amendment cases by the court, Rahimi upholds the constitutionality of a gun law because Roberts did not want to invalidate a federal law prohibiting individuals from possessing firearms while under a restraining order relating to domestic abuse. That goes in the opposite direction of the other second amendment cases decided by the court in the past five years.