> If, as your post seems to be recommending, such regulations were abolished, Japanese farmers would pretty much cease to exist because of their inability to compete with cheaper imports.
Good, they can do something more useful with their time because Japan does not have a comparative advantage in farming. Having farms in Japan is very inefficient, since there are better regions to grow these crops.
Sure, you can't displace these farmers tomorrow, but slowly increasing the imports is a good idea. For one thing, it would decrease the cost of living for the average Japanese person, even if farmers are negatively affected.
Why is a farmer more important than a city dweller?