The question here in Chinese is: 如何理解佛所说，不能证人入罪这句话。
My translation for 证人入罪 would be “to testify or provide evidence against someone to proof his/her guilt”
From Venerable’s discourse, Buddha has said that we should not do this action.
Let’'s hear the discourses from both Venerable Ru De and Ru Jun.
My take: It is very easy for one to justify their action that they are providing the testimony or even accusation so that society benefits from it and the person “learns” from the resulting punishment. However, commonly, our intentions are not pure and there is a element of malice or ill intent. The Karma that comes out of it will thus harm all parties.
In fact, if one understands the principles of Karma, one would not want to be involved in the unhappiness of another party. It boils down to a person’s motivation.rather than just looking superficially at the action and judging whether that is good or bad.