Why is it an "economic massacre"? If it is, how come the Western manufacturing and farming industries are complaining so much?
Because complaining is part of business. Especially if you're a farmer, but also if your a businessman in general.
I call it an economic massacre when we sell parts if our chicken to western Africa so cheap that it destroys their own agricultural market, which is the only sector they have that may be competitive in the near future on the world market. But they need to improve it first, what they can't when they are flooded with our agricultural goods. Therefor, tariffs would help them.
Except they don't improve it. They tried the same thing in Latin America and Africa in the 60's and 70's with ISI. High tariffs and subsidies of domestic manufacturers just shielded inefficient companies which collapsed under competition when the system collapsed. I don't see why trying to protect their farmers would lead to anything but a lowering of agriculture standards, with the lack of competition allowing them to behave less efficiently.