Parental alienation is bad science. The evidence that was presented is not based on good research. It is not a real problem. It's a problem that is used by coercive men to gaslight and discredit their partners, and it is a big problem that it is taken seriously in the courts. It's a weapon used by abusive men.
I would absolutely not give it any credence whatsoever in the court system. It's bad science, junk science, and courts shouldn't recognize it at all.