I didn't say his motive was irrelevant, I said that "killers kill for a reason...the reason doesn't matter nearly as much as the killing itself."
Of course he had a "motive:" ALL killers do; but "motive" is meaningless unless acted upon; for example, I very much dislike Trump, the man, so I'd arguably have some form of undigested "motive" but I am disciplined and law-abiding enough not to allow my animus to act out: unlike the Mormon Moron I'd never attempt to threaten or actually hurt Trump or anyone or any thing else I find reprehensible / intolerable.
But I see lots more trouble coming on the horizon, given the politicization and dumbing down of America and the deterioration of morality and guardrails.