It was a program called Nature and was discussing the impact of more folk visiting the countryside on sensitive landscapes and wildlife.
I thought it was pretty balanced. Dog walkers got more stick than mountain bikers,and the chap did stress that it was only a tiny minority of mountain bikers who were idiots (and he’s right). He also stressed that there was no question of restricting access; it was simply about making more folk aware of the impact they might have.
And let’s face it, there is a small minority of “me first” mountain bikers only interested in their own (supposed) right to ride wherever they want, regardless of how much damage they do.