In standard English, a clause with the second person pronoun "you" as the immediate subject always takes the same verb form used for a plural subject.
However, your examples have relative clauses, where "you" is not the immediate subject of the clause. The subject is instead the relative pronoun "who". "Who" in turn takes the personal pronoun "you" as its antecedent.
Clauses with the relative pronoun "who" as the subject have somewhat variable verb agreement. However, it would generally be considered correct to use the same agreement as "you" in your examples. A related question:
Is "It is you who are mistaken!" correct? That would give "It's you who never lie" and "It's you who purify".