If you are keen to find out why most of the Muslims will roll up their clothes above the ankle, then you should have some historical prospective of Arab culture and the early era of Islam. Letting their long dress dropped down on the ground was a symbol of Arab proud and their disdain to the poor and non-Arabs. It was done by Arabs who were rich and proud of their heritage and was considered as Pride.
This was nothing to do with Islam, however, it was advice to the Muslims to roll the clothes up don't drop them on ground when walking and standing. In order to discourage and remove this habit from mostly Arabs it was asked to roll the clothes and pull them up, instead of dragging them on ground behind them.
That was it. Don't make a mountain out of mole hill and start to target the scholars and religion.