Shoju and Shakubuku
See Kaimoku-sho, Open Your Eyes
When the land is full of bad persons who are ignorant about Buddhism, the persuasive means, Shoju, should be take precedence as preached in the "Peaceful Practice" (14th) chapter of the Lots Sutra. However, when there are many slanderers who have evil thoughts against the True Dharma of Buddhism, the aggressive means, Shakubuku, should take precedence as preached in the "Never-Despising Bodhisattva" (20th) chapter.
That is to say,
Generally, when evil sects which slander the eternal Buddha Shakamuni and His teachings have a great deal of influence, you have to do Shakubuku.
Individually, you should do Shoju for the believer of other religions, such as Christianity and Islam, who are ignorant about Buddhism. However, you should do Shakubuku for the believer of evil sects, such as SGI and Nichiren Shoshu, which slander the Buddha Skakamuni and His true teachings.
Shakubuku of "Never-Despising Bodhisattva" is to tell the right doctrine forcibly for people. Please see again it. Those who slander Never-Despising Bodhisattva become his disciple after having experienced Hell. This is Shakubuku.
Even in Japan, many priests of Nichiren sects don't criticize those sects who slander the eternal Buddha Shakamuni, because they want to prevent troubles with other sects, and want to behave like a virtuous man. Then, they try to expound "Never-Despising Bodhisattva" as Shoju means. They are not disciples of Nichiren shonin. They are opposing to the doctrine of Nichiren Shonin.
In Shakubuku method, you should criticize wrong doctrines clearly. But it doesn't mean to behave offensively to others. In Shoju method, you should not criticize wrong doctrines clearly. But, it doesn't mean to behave passively to others. Nichiren shonin recommended Shakubuku method as the practice of Mappo era. If you take Shakubuku method, opponents become offensive and slander you, because their doctrine is matter of life and death. So,you have to practice the forbearance and the assiduity necessarily. You have to make efforts to get the protection from good deities. You have to overcome difficulties to gain the Buddha's confidence.
If you possess high ambition to become a Buddha, you will encounter many difficulties that you should overcome. Therefore, if you encounter many difficulties, you should possess high ambition to become a Buddha.