“Scott Ritter is a twice-arrested, convicted pedophile.”
https://en.wikipedia.org/wiki/Ad_hominem
There are many creeps in their personal life that have important things to say on areas where they have expertise.
Alan Turing is one example—there are many many others.
I see your point, I really do. But by golly, there are some people whom I’d rather not quote, or use as an information source. I would look elsewhere. The problem is when the creep is the only (or the the best) source. Then what? Then you’ve just got to weigh the plusses and minuses. And so good folks will reach different conclusions.
As for Alan Turing, he was, shall we say, unusual. But he was not a predator. Scott Ritter is a predator.