Earlier quoted context omitted.
A few hundred years ago, men in many countries were allowed to beat their wives and children with few restrictions. Need I also mention that slavery and child labor were legal? Historical legacy is absolutely no rationale for continuing to cause needless suffering in intelligent beings.
Who is to say what is "needless"?
There's a pretty valid point to be made that you don't NEED to eat whale meat. Or Cow meat. Or any meat really. There are economically available options in most areas that would allow for a nutritionally balanced, vegetarian (possibly vegan) diet.
This is specifically true about a developed nation like Japan.
There's counterpoints to be made (not all farm land is suitable for crop farming, so using it for husbandry is valuable; a complete one day flip without a slow phase out of meat would be economically devastating; freedom to eat animals is my right, etc) but you can't really say you NEED to do it. Science and nutrition doesn't back that up, and the economics are hazy at best.