The prosecution’s experts were claiming they could identify the screamer and hear things, defense’s experts were simply saying you can’t do that reliably, so excluding prosecution’s imaginary evidence eliminates need for both.
Actually it only excludes the states ‘expert’ witnesses. It doesn’t exclude the defense’s witnesses from being allowed to state that it is impossible to derive any conclusions of who is screaming. It also doesn’t excludes the suspected ‘witness’ who heard the screams and thought that it was Zimmerman.