As far as Horowitz is concerned, I am just old enough to have known about him and what he did, said, and wrote, in REAL TIME. I was, and still am, a RABID anti-Commie and a CONSERVATIVE, back then, saw and heard, with my own eyes and ears, what was going on in the late '60s/early '70s, in NYC. It's truly SEARED in my brain and soul and hell yes, I can tell you the year/s, where I was, what I was wearing, and who I was with, if I was with anyone, and what I said to others and what they said to me...WORD FOR WORD, still.
It's really not easy to get over the above and/or forgive those responsible for it and what was built upon it all, which is how we got to where we are today.
OTOH...okay, it was a sort of Saul to Paul thing, except NOT through a visitation from GOD nor Jesus.
David probably wouldn’t disagree with your characterization of what he was doing in the past. He may describe it, but he doesn’t excuse it.
Some of the neocons I’ve met on the other hand are just fine with their personal history. Seem to think that where it conflicts with conservatives, it’s conservatives who were and are wrong.