Not entirely true in my anecdotal experience. Most of the original deniers I know personally now say that climate change is real, just that it’s not man-made and there’s nothing we can do about it. I remember around a few years ago I even convinced my boss that climate change is in fact real (he couldn’t come up with a valid reason to explain picture and video evidence), but he refuses to accept humans are causing it. It’s still equally frustrating, nonetheless.