Strange one this. What probably has happened is Froome really struggled with his asthma and has had far too many puffs on his inhaler presumably so he could compete at a normal level... BUT:
I suppose it could be argued that he took loads of inhaler to gain an advantage on that particular stage but I don't know enough about the drug in question to even know if sucking on an inhaler on a stage would give you an advantage towards the end of it.
Rules is rules and there was a limit and he broke it. We'll wait and see if he's sanctioned. I'd guess he won't. Froome has plenty of funds for scientists and lawyers to argue his case.
But yet again people not familiar with cycling / anti-doping will now consider Froome a serial doper and no better than Armstrong and all of this has given the Anti-Sky / Tin Foil Hat brigade a load more fuel. Sigh.