1) I've previously explained the concept of "everything is political" as being like the term "encoding". Every message is encoded, the only question is how.
2) I'm fully aware that my project(s) are "political", and I make tradeoffs to those ends!
3) It's easy for me to dismiss that 10x developer argument, those privileged enough to contribute as much as I do to my work rarely knows what needs to be implemented.
To my mind, "keep politics out of..." (The project, the dinner table, the office, etc) are more about our understanding that not all of our behavioural standards can be synchronised in all groups. To reduce effort, some topics fall into "agree to disagree" by default. But some of these topics have become important to foss projects and so they have to move into "we must talk and agree about this now".