Some might claim the BSD community's focus on security to be a purity spiral, but it's arguably produced things of value. Having small communities around who occasionally drive themselves to the extremes of a particular idea can useful for broader society.
That's not the sort of purity that the article is talking about. The article is talking about purity for purity's sake -- a relative and subjective set of rules that exist to provide levers of power.
A singlular and uncompromising focus on OS security serves an absolute and objective purpose, that being... OS security. To the extent that it is objective, it is less subject to being coopted for political purposes.
