I keep hearing the same three words being used to describe the recent past of Kirk's killer- "more politically active".
As vague as the phrase itself is, two facts bear hint that what is not being said tells you enough.
1- The phrase is ubiquitous. It showed up in every breaking news article I could find from shortly after his capture on. So neutral a phrase repeated so often softens and minimizes what happened to him. He was so obviously radicalized, but this phrase has eclipsed the use of that word.
2- It really doesn't look like he really did ever become "more politically active". No joining anything political. No real social footprint on any platform. Certainly no manifesto.
I think he radicalized himself, almost completely.
He turned hard right in a very rightwing state. Very easy to get 'more politically active' towards the right without pushback. It doesn't look like he got any pushback at all from his "Very MAGA" family. Also, you could probably veer very hard right in Utah without raising any eyebrows, let alone alarms.
Had he gone left, they'd be using a different phrase.