I was at school in the UK in the 1970s and 80s. I am a supporter of the concerns over global warming today, including the man-made element. And I can absolutely confirm that we were being taught about coming ice ages, within our lifetime, in my school geography lessons.
It concerns me that people are saying this is a fallacy just because one image is faked. It isn't, this happened and there is evidence for that teaching. Whether it's right or not is entirely different to whether it actually happened. 'Our' side, the side wanting more action on energy transition and the side on which I cheerfully identify myself as being on, just looks foolish if we start pretending contradictory teaching never occurred. It is not, and should be not, a surprise that views change as more evidence is gathers.