Agreed. The level of aggressive gatekeepers is just crazy, take Linux ARM mailing list for example. I found the Central and Eastern Europeans particularly aggressive there and I'm saying this as on myself. They sure do like to feel special there, with very little soft skills.
Sign extension bugs are the worst. Silent for ages then suddenly everything is on fire. Spent a lot of time in C doing low-level firmware work and ran into the same class of issue more than once. Nice writeup, congrats on the patch.
In my opinion, unwritten rules are for gatekeeping. And if a new person follows all the unwritten rules, magically there's no one willing to review.
I think this is how large BFDL-style open source projects slowly become less and less relevant over the next few decades.