It is reasonable to arm yourself for the defense of yourself and your loved ones when others have expressed an interest in killing you. That is not a radical ideology. This is true for all faiths, genders, nationalities, attack helicopters, whatever the hell you identify as.

Had there been an armed response at the NZ mosque, the death count would have been significantly lower.

No government is responsible for protecting your or your loved ones lives - You and you alone are responsible for your life. You can either shoulder that responsibility or shirk it. Sounds like this guy wanted others to shoulder that responsibility and protect the community. I find that admirable.