Why do the FIA have such a vendetta against off throttle blowing? It's free speed FFS. It doesn't affect the entertainment in any way, unlike DRS which they hideously introduced to the sport and persist with to the detriment of both the entertainment and integrity of the sport. …
Because it is completely irrelevant to road cars and as such presents one of the biggest arguments used by the 'greens'. And no; it is not "free speed": it comes at the cost of roughly 15% extra fuel consumption. Neither does it add to the spectacle whereas it could be argued that DRS does as is intended.
To put it bluntly, fuel is designed to drive an engine; it is not designed to blow wastefully into the wind for some other purpose. Even a fast-jet's afterburner - where fuel is thrown straight into hot exhaust gasses to produce extra boost at enormous cost in terms of fuel-efficiency (rather like using a jet engine as a semi-rocket) - still uses that fuel to provide power. But blowing hot exhaust onto aerodynamic surfaces does not.
In the purest sense, it is 'wasteful' (i.e. not in the interests of fuel-efficiency), since it requires extra fuel which has no bearing on engine performance.

