Thank you Cécile. I wonder why it is not 'Ce qui' instead? (Ce qui vous dîtes là est excessif) as the fact that 'vous dîtes là' is a subject, and subject should use ce qui?

The subject of the sentence is vous and the object is ce que. You can only use ce que if it is the object of the sentence; if it happens to be the subject, you use ce qui.

Furthermore, ce que/ce qui is used for inanimate objects and que/qui for persons.

Maybe an example is in order:

Ce qui se passe est intéressant. -- What happens is interesting. (Here ce qui is the subject.)
Ce que tu dises est intéressant. -- What you say is interesting. ("You" is the subject and ce que the object)