I think this is turning cause and effect around. As a parcel of gas moves from a region of high pressure to a region of low pressure, there's constantly a force acting on it, which means it will be accelerated, and thus speed up. But I'll admit that doesn't give an intuition for why blowing air definitely does lower pressure, like in the classic experiment where you blow in between two pieces of paper and they move towards each other because the pressure between them is lower than atmospheric.