Japanese atrocities during WW2 are documented. The comment was about Chinese vehicle sales in Japan. But Chinese vehicles are selling like gangbusters everywhere else. It is important to understand the context. There is animosity between these countries going back quite some time.

Do you think South Koreans would buy a North Korean made car, even if were better? Would Israeli's buy a car made by Iran? Would Indians buy a Pakistani made car?

Also, Japan's #1 export is automobiles. They have the future of their country tied to the automobile industry which is dying (China overtakes Japan in auto exports with boost from EVs :https://asia.nikkei.com/business/automobiles/china-overtakes...). Japanese wouldn't be super interested in buying Chinese cars and destroying their domestic market as well.

How the massacre still haunts China-Japan relations: https://www.bbc.com/news/articles/cp89ed9j5ygo

https://en.wikipedia.org/wiki/Nanjing_Massacre

https://en.wikipedia.org/wiki/Category:Japanese_war_crimes_i...

freetime2 has a better explanation (sibling comment): https://news.ycombinator.com/item?id=49841283

Not familiar with the gaijin concept?