I think you are right that the racism example is better than the subway hypothetical.

Konkvistador's use of the word political to only reference being active in the process of selecting public officials is quite conventional. For reasons based on feminist thought, I think this understanding artificially restricts the sorts of problems and approaches that can be addressed. In other words, I think the conventional definition is wrong, in that it doesn't actually reference everything that it seems to be trying to reference. Thus, I prefer to say that "The personal is political."

But the other issue I had with his original comment was that the OP was talking about having an open mind about ideology, not simply politics. To the extent that the OP was reconsidering his ideological commitments, I was to suggest that committing to some type of apolitical stance (either under my understanding or Konkvistador's) was not necessarily optimal.

However, the non-involvement principle does seem to recommend against that particular method of opposing racism. If you consider this a flaw, that seems to be a perfectly coherent reason to reject the principle.

Yes. Life doesn't come labelled "racism issue." If you don't think about what you'll do in ambiguous situations ahead of time (which being apolitical suggests you shouldn't), you won't act. Getting things done isn't often polite, as this comment notes.

Clearly, we have insufficiently formalized what it means to be apolitical.

A few comments up I linked to the wikipedia definition to formalize my usage:

The state or quality of being apolitical can be the apathy and/or the antipathy towards all political affiliations.

I think I'm basically pretty much at antipathy. I have a negative and I think pretty justified attitude towards those trying to enthuse me for political affiliations as people trying to hijack my goals for their own purposes.

I always assumed that it meant following the relevant social norms of whatever society one finds oneself in, avoiding political argument, and taking a carefully crafted "neutral-stance" on political issues.

That is how I intended to use the word. Considering oneself neutral in the great tribal struggles of one's time, aids one in having a better map of reality. It also helps to avoid hijacking by predatory memes.

I certainly agree that if the non-involvement principle recommends against exercising laudable virtues, then the principle is a bad one.

I don't know why anyone would choose to describe this as the primary use of the word "apolitical".

Edit: I didn't mean to imply you did.