It is possible to explain that incident using the 'BBC is hopelessly left-liberal biased' theory. The most well-known advocate of the benefits of strenuous exercise in recent decades has been the left-liberal icon Jane Fonda.
Fonda invented the idea of the celebrity fitness video, and maybe the whole idea of the fitness or workout video, back in the early 1980s. One of the central themes of the Fonda style of exercising is that you were encouraged to exercise to the point where it hurt, this idea being summed up in such catchphrases as "feel the burn" and "no pain, no gain". I can imagine somebody within the BBC noticing that the original article, which implied strenuous jogging might be dangerous, did not tie up with the teachings of Jane Fonda.
The theory that strenuous exercise is good for you has been given a new lease of life in more recent years with the claim by some medical researchers or sports scientists that the exercising activity can be reduced to a short burst of intense exercise lasting only a few minutes, instead of the more commonly adopted time-consuming sessions of half-an-hour or so. One of the BBC's most prominent employees, Andrew Marr, decided to follow this advice in 2013 and managed to give himself a stroke:
Marr blamed newspapers for putting the idea in his head of trying out intense exercise, but as I remember it the BBC were the biggest promoters of this fad, and even went as far as broadcasting a Horizon science documentary in 2012 publicising it called "Horizon: The truth about exercise".