No, I am saying that allowing Roof to claim he killed those folks for a reason is to allow him some form of legitimacy, given that one mans freedom fighter etc etc. Like it or not, throwing the term "terrorist" around for this kind of thing does make people think of PIRA, of the Irgun, of the Red Army Brigades, of Baader-Meinhof and the rest. He isnt one of those.
Roof is a murdering scumbag who shot nine innocents in a church. He really doesnt need any other label.
Roof earned "terrorist" through his heinous actions and motives. Terrorism is what he did, so a terrorist he is. It is not an honorific title. It does not legitimize or validate anyone. If it lumps him in with other terrorists, who were also murdering scumbags who killed innocents in churches, or elsewhere,* then the word has done its job. The point of labels is to label things, and he is correctly labeled a terrorist. (All this mania against labeling things is rather stupid, isn't it? Our ability to label things is called speech, and it is one of those things that makes us higher than the animals.)
Roof, being human, had a label for those he killed. He had a reason for killing them, and not killing some other bunch of people. In that way, he's like the humans that flew airplanes into the World Trade Center and not the Taj Mahal. That a man has unreasonable reasons does not mean he has no reasons.
*I'm talking about terrorists, not freedom-fighters.