Yep its made that way. My yanmar is the same way. It was made before they thought of safty stuff and made things simple and reliable with as few parts as possible. You just had to remember if mowing up to a fence or barn you cant cluth and stop, the mower inertia will keep on pushing you foward.
My little yanmar is the same way. get a $40 over run clutch and solve that. It allows the bush hog to free wheel and the clutch "ratchets" like a socket wrench going backwards. There about 9"s long and slip onto the pto then you hook the bushhog drive shaft to it.