"Let them be resentful, and I will not forgive any of them." This comes from an essay written by Lu Xun shortly before his death, called "Death". This sentence expresses his attitude of never compromising or reconciling with his enemies, and insists on his consistent moral stance. Even death cannot dissolve this confrontation.
The "new type of people" probably refers to those who have some Western Christian connotations. They always say something like forgiveness before they die, but Lu Xun, as a soldier, is not so easy to do so. Compromising people also have doubts and disbelief about this kind of forgiveness, so they say that they let their enemies hate themselves, and they will never forgive the mistakes they made.
Extended information
Due to his serious illness, Lu Xun had thoughts about his death and considered leaving a will to his relatives. In Lu Xun's will, in addition to informing his relatives about his funeral affairs, he also left his lifelong combat experience to future generations.
He hoped that relatives would "not take things promised to you seriously" and "never get close to someone who hurts others but opposes revenge and advocates tolerance." This is a wise saying summed up by Lu Xun from the complex life and struggle, and it is also the principle that guides our life and struggle.
In the long, sharp and complicated struggle, Lu Xun deeply realized that to forgive and be kind to the enemy was to be cruel to the revolution, so he stated in the article that he would not forgive the enemy until his death. This spirit of not forgiving the enemy until death is a concrete manifestation of Lu Xun's consistent uncompromising and fearless fighting spirit against the enemy.
Baidu Encyclopedia——Lu Xun