When the New Yorker interviewed me about an article  they were preparing over the political impact of Charles and David Koch, I emphasized
that when I knew Charles Koch in my high school and early college years, he
was a sincere libertarian, not a garden variety right winger or
oligarch.  Ideas and ethics mattered.  So did science.  For him libertarianism meant commitment to a non-coercive society.  Charles had set me on my
intellectual career through his generosity, and come out publicly against the
Vietnam War in a state and city where that was considered unpatriotic.  My personal memories of him were
entirely pleasant. 

In later years it seemed to me both of us had moved away
from libertarianism, me towards a more generic liberalism but always from an ethical position that opposed coercion, he in more
conservative right wing directions.  But I thought Charles still might be a
libertarian trying to find a way to be effective in culturally inhospitable Kansas.  I did my best to put as sympathetic a
face on the Kochs’ activities as I could, given that I opposed most of what Koch supported politicians stood for.  (I say “most” because maybe they stand
for something worthwhile I haven’t heard about.) 

Recent events in California as well as their rather selective approach to freedom of speech (also in previous link) have
demonstrated to me that there seems to be little libertarianism left in the
Kochs beyond rhetoric as well as considerable abuse of the power of their immense wealth to
harass with lawsuits and hired goons. 
The linked article indicates even the sanctity of contracts and
voluntary agreement, libertarianism’s most holy grail, can be overridden when Koch
money finds it inconvenient. 

It’s sad as well as scary.