What ruled that anyone arrested must be read a statement of their rights before being questioned or their statements cannot be used as evidence against them in court?

The US Supreme Court ruling in the case of Miranda v. Arizona established this right.

However, there is no requirement that you be advised by the arresting officer, immediately upon your arrest, only that you be read your rights before actual interrogation about the particular offense commences. .

If there is any question about the admissibility of the evidence against you, your defense attorney will raise it at the appropraite time.