Or the manager could just get everyone to stop their "continuing wankery and bickering over each developer’s subjective opinions". If you're a professional, you should act like it.
Most of my friends and coworkers use DeWalt, while some use Milwaukee, and there's even a few oddballs who use Makita, but I've never heard any 'bickering' about it.
I don’t agree with the analogy. The interface of a drill is much less complex and is basically the same over all brands. The longevity and power may well differ. Drill bits are standard and work as well in a Makita as in a DeWalt. I don’t think that tradesmen personally identify with their drills. Drills are not political.
Thus, EditorConfig! It's a standard for editor configuration, and is basically the same in all text editors.
Drill bits are standard, but lots of other tool interfaces are not. Batteries are not at all compatible, for example, and not even within the same brand (different voltage, different battery chemistry, ...). When someone's Milwaukee 18V lithium battery dies, and there's only a DeWalt 20V charger, nobody makes snide remarks about brand, any more than if you had the wrong size wrench for the bolt you needed to tighten.
It's true that "drills are not political", so why would you allow developers to claim that text editors are? That is a social problem, so it requires a social solution. You seem to keep implying that software developers uniquely posses an inability to behave reasonably in the presence of alternatives.
Most of my friends and coworkers use DeWalt, while some use Milwaukee, and there's even a few oddballs who use Makita, but I've never heard any 'bickering' about it.