Phos did absolute nothing wrong. Her actions are of sound mind and just.
While i know some would be joking about this ive found alot more dont actually realize just how much phos lost the moral high ground when they went to the moon.
The earth gems deserved to have their inaction and mistreatment of phos come back to bite them......322 years ago.
On the other hand now though if the old phos was a part of the gems during the 220 years with no lunarian attacks they would have been treated much differently. Their antics would be looked upon fondly (not as exasperated) and they wouldnt have been treated nearly the same way.
Cinnabar was accepted as a member that they liked and worked to include even outside of their usefulness in fighting phos. That after literal millennia of being essentially a self-imposed social outcast that the other gems were also wary of due to the literal poison they breathed it took only 220 years (no time whatsoever) for them to be reintergrated into gem society and universally liked.
Now though destroying the gem society isnt going to do literally anything. It will only destroy the very thing that phos initially wanted and not even get what the lunarians wanted.