Perhaps racism isn't the right descriptor.
Japan has a caste system that puts India's to shame. It's smaller in the number of people living in the lower tiers, but the effects are amplified to a high degree.
At least India puts some effort, futile or not, into forcing representation for its untouchables.
In Japan, a member of the untouchable caste is actual, literal, human garbage especially in the western parts of the country.
It is illegal for parents to investigate the background of their children's potential marriage partners in order to determine if they are a member of an untouchable caste.
Investigations still occur regularly.
Anyone who claims that it is not still a problem is either lying, or is a Japan-obsessed foreigner whose impressions of the country are based on a weeklong trip to Tokyo.
I'm willing to bet that many of the children refusing to go to school are those with the "wrong" family name.