These more draconian measures seem more in keeping with the commentary of v 30a, “To do away with the appearance of hating them all.”
The logic of the whole inscription is: “If you want to pray to YOUR God, you must become my slaves – or die. If you want to sacrifice to Him as well, you must also be branded. But if you agree to worship MY gods (and myself) you will live as free people, with equal rights as Alexandrian citizens.”
In more detail:
v 27 Ptolemy’s intent is revealed and an inscribed pillar set up at the Temple’s tower porch saying …
28a Entrance to Temple is denied to all who wish to make burnt offerings
v 28b All Jews must be registered as slaves, (resulting in further removal of rights)
v 28c A death warrant issued for all Jews who resisted.
v 29a Stipulates a concession – registration and also a visible branding
v 29b Declares if both conditions are met then they would be “set apart for this now conditional permission to kill” (by sacrificial burnt offering).
v 30a But they are now slaves with far fewer rights than before and with a devastating limitation of their religious freedom, unless further humiliated by branding. To appear merciful, Ptolemy then offers …
v 30b An alternative to all the above, is the initiation into the rites of Egyptian gods, then better rights are granted than they had before, as full Alexandrian citizens. (But they would no longer be God-fearing “Jews,” but fulfilling Ptolemy’s plan to have all in Egyptian polytheistic worship, which included honouring himself also, thus fully avenging his previous humiliation by the Jews.
v 31 SOME politically ambitious Jews saw an advantage to doing this and complied (esteeming entrance to Jerusalem’s temple abhorrent in comparison)