Nobody had the legs to go with the Jumbo couple.Asgreen was at the back of the peloton about 1km before that climb and couldn't move up in time. Ghirmay was third wheel and he let it go and since the climb was essentially a narrow strip of tarmac as there were no barricades it was impossible to pass without going onto cobbles. Bit of a major mistake from Asgreen.
They would have passed Ghirmay, even on the cobbles, if necessary. They just couldn't.