Actually (counsel to our dear Jazzy Belle aside),
The use of the apostrophe in english plurals has a long history. The texts of Shakespeare do occasionally use it.
Victorian grammarians attempted to standardise English in line with latin and created artificial rules to do so. (Sounds like another bunch of old timers.) So they said "It is I"
Not "It's me" as in french etc.
The apostrophe problem arises because in the days before radio or TV ironed out fine distinctions of pronunciation, people still said "eggis" (pl) or "dogges" (pl) The addition of the unnecessary ( ' ) is to do with pronunciation and provenance of the writer's ancestors.
SIDEBAR - How like Fred Franz am I ????????????