It's 'who (is) not named you', i.e. the other person who is not you. Not saying the verb 'be' is a feature of this speaker's dialect.

The speaker is referring to a third un-named person who did not name the first person. In other words the third person did not reveal nor divulge the name and identity of the first person. The speaker has a small speech problem and says things that are not exactly grammatically correct such as. "who don't tell you about all that other persons" <- not quite grammatically correct. "Who did not tell you about all the other people" <-- is more grammatically correct.