William, well said, we share this sadness:  "My heart is heavy with the deaths of two very heroic men from this act. May they rest in peace."
However I find it hard to believe  you wrote "This was nothing but a heinous act carried out by a deranged, mentally disturbed individual."  You  think ideology and the social climate had no relation here?  His fondness for Nazi material is irrelevant?  The huge nation-wide spike in hate crimes isn't a factor?
What do you mean by "deranged mentally disturbed individual?"  You've discerned he's mentally ill and will be found "innocent by reason of insanity?" 
And what's deranged?  Weren't many of the Nazi leaders, especially Hitler and Rudolf Hess, "deranged?"  In fact, isn't most of our behavior a mixture of our inner mental state and social context?
The challenge,as I see it, is to find a way to oppose this wave of angry hateful rhetoric without trying  to deny the free speech these haters are exploiting to mobilize the unstable like Christian.