3 sieves

A man came to Socrates and asked:
- You know what your friend told me about you?
- Wait, Socrates stopped him. Ask first what you are going to say in three sieves.
- Three Sith?
- Before you say anything, you need to sift through it three times. First, through a truth sieve. Are you sure what you're gonna say is true?
- Nope. I just heard...
- Very good. So you don't know if it's true or not. Then we sift through the second sieve - a sieve of kindness. You want to say something good about my friend?
- Nope! Opposite!
- So," Socrates continued, "you're going to say something bad about him, but you're not even sure it's true. Let's try the third sieve, the benefit sieve. Do I really need to hear what you want to say?
- No, that's not necessary.
- So, Socrates concluded, in what you mean there is no kindness, no use, no necessity. Then why say that?