I love it, Google makes a big deal of RankBrain back in 2015 and since then has been trying to get SEOs to focus on other things, outside of RankBrain. I mean, Google is right - SEOs should really not focus on RankBrain. It is a query interpretation algorithm and doesn't directly influence ranking.
Now you have John Mueller of Google posting on Twitter about how unfortunate it is how SEOs are writing articles about RankBrain because it is directing SEOs down the wrong path. John wrote:
I think that train has left the station - we use machine learning in so many places, it doesn't make sense to try to single out RankBrain and to guess individual factors involved. Ranking is complex. Sorry for not having a simple answer, but IMO the question is irrelevant :).
— 🍌 John 🍌 (@JohnMu) November 5, 2018
I mean, can you really blame SEOs. We had a Google tell SEOs that RankBrain was top three in the ranking factors. Then they spent years trying to tell SEOs to stop trying to optimize for it - it doesn't work that way. Heck, even Googlers are confused by RankBrain.
My advice - stop citing RankBrain, it really isn't something you can control. It is just how Google understands queries entered into their search box.
Forum discussion at Twitter.