I think if somebody directly offends you by calling you something you don't like, then from first-principles, it does seem like you're always okay letting them know that and seeing if they mind stopping. And most kind people would.
But in the meme-case it wasn't the lady in the meme asking people to stop, it was just some random girl on reddit. Same with the cargo-culting, I don't think the cargo-cults themselves are objecting, rather it is somebody objecting on behalf of another group.
Or the case of how we name our git-branches is even more indirect (since nobody is calling anybody anything, except a git-branch).
I'd love to hear some from-first-principles, emotionless arguments with clear proposals (e.g. If x% of people think term Y offends group Z, at what threshhold do we care? And does only group Z get to vote?).