There is usually a sidecover on the bike, shielding any direct flow to the filter inlet.
If the scoop faced forwards, it would also gooble up rain and other detritus from the road.
Also, if the scoop faced forward it might create more positive pressure in the carb bore and reduce the amount of flow through the fuel metering jets, leaning the mixture.
If you want ram air to be of benefit, you'll need the same pressure on the fuel vents for the carb float bowls, as is presented to the carb throats.