You don't hear anyone calling their biological father "holy" father! There is but only one father in the entire Bible addressed "holy" father and that is God the Father. Hence, it is blasphemous to call the Pope "holy" father. He is usurping a title that the Bible ONLY gives to God.
Can you find ANYWHERE in Scripture where the epitaph "HOLY Father" is ever applied to ANY man on earth at ANY time on earth?