you didn’t read the link.
I did read the link. It was correct up to the point of “. It does not mean “more serious”. It refers to those punishable offenses that only apply to high persons, that is, to public officials” and then became erroneous conjecture. The origin of the phrase in English law referred to applying common law to the behavior of nobility. In this case ensuring the laws of the people apply to the chief executive.
On second thought, erroneous is strong. A following of Blackstone and Burke would lead an author to the point of including the vagueness of behavior unbecoming of the office.