Before he entered the theater, he purchased guns, whether legally or illegally, under a framework of laws and regulations governed and negotiated by politics; in the parking lot outside, he was arrested by a police force whose salaries, equipment, tactics and rights were shaped and determined by politics. Holmes' ability to seek, or to not seek, mental health care; the government's ability, or inability, to lock up persons deemed unstable — these are things decided and directed by politics. You cannot "politicize" a tragedy because the tragedy is already political. When you talk about the tragedy you're already talking about politics.