There are a few points you need to keep in mind when understanding "the issue of Christianity and Christian censorship of expression in Japan."

So I'll explain them step by step.

①
The basic ethics of the current restrictions on expression are based on the Irregular and Unjust Acts Ordinance, which was established in the Meiji era with the aim of eliminating unequal treaties and aligning Japanese ethics with those of the developed Christian countries of the time.

However, since the police were involved in enforcing the ordinance, the police's ethics were similar to those of Christian countries.

As a result, an ethical affinity was created between the police and Christians.

②
The majority of converts to Christianity in East Asia were Confucianists.

However, in Japan during the Edo period, the Tokugawa shogunate suppressed Christianity.

Confucianism was only followed by a small portion of the samurai, who were the ruling class during the Edo period, so even after the Meiji period, Christianity was mainly carried out by urban dwellers and the upper classes.

On the other hand, in China and the Korean Peninsula, where Confucianism was thriving, it was able to gain many believers.

As a result, Japanese Christians began to have personal exchanges with Christians, especially on the Korean Peninsula.

③
During the promotion of Westernization after the Meiji period, probably due to lack of financial means, priority was given to boys in the Western school system.

Because many of the people in charge of educating women were Christian pastors and priests who came to Japan, a high proportion of women who received higher education became Christians.

As a result, many conservative women were Christians, and the preconceived notion that "conservative ideology = Confucianism" did not apply.

In addition, many teachers and nurses, professions available to women at the time, had received Christian education, so there is a high proportion of Christians in academia, medicine, and welfare.