See bad thing - link to Japanese people as a whole or in general, rather than the individual.
It's an easy mistake to make. Especially if you do ever hear it in the inverse direction. "Foreigners do X or Y", etc.
If he aimed to replace generic instances of 'Japanese people' or 'in Japan' with specific reference to the instance or person, I think he'd have had a better time in life.
And yes, it's difficult to encounter any amount of racism and not feel that the group of people that the racist person came from, do not in fact as a whole demonstrate racist behaviours in general. Obviously not at a higher cognitive level, but at an emotional reacting to a certain way of having been dealt with or treat.
But it's absolutely necessary to stop the generalisation, even if only for one's personal mental health. It serves no purpose other than wiring our animal brains up more strongly, to think of us vs them.
And try and notice it more often in Western media too. Any time there is a mention of someone's race, see whether it would look out of place with Black or Latino or Asian replaced with white.
It's often a completely irrelevant piece of information.
As the use of the word Japanese is often irrelevant in this post.
Yep lot's of terrible people in lots of places in the world, and the fact that they were Japanese in this instance is more related to the fact that they were born and brought up in Japan than some inherent generic flaws with an entire country of people.
And yes Japan has problems that aren't in other parts of the world, and vice versa. It still doesn't befit using `X people do Y` type generalisations.