As best I can tell, the guy was more like a god-in-his-own-mind than having strong Prog or conservative ideas. Take my opinion and a tenner to Dutch Bros and you'll get ...
While he had some sort of list in his SUV and the names were all Dems, it has a sign that it is at least 6 months old, as that is one of the persons listed died of (IIRC) cancer. Also, two of those he shot were not on the list. Whatever the purpose of the list, it has signs that it may not have been a "hit list".