I agree that the PCL-R test is inadequate - so passing it, is no more valid that failing it.
My criticism of PCL-R is that its easy for an amateur or non professional to use it.
If someone with the experience and calibre of Professor Vincent Egan or forensic psychiatrist Michael Stone for example conducted the PCL-R then in that sense its a perfectly valid tool.
But if for example "TV psychologist" like Emma Kenny conducted the PCL-R test then I wont care too much about the result.