Can someone elaborate on how community Greed only rules get established?

[Ninster]

There are also items that cannot be needed if you are of different gender, like those Thavnairian series that can only be needed by female.

Oh ok, thanks. All the Thav items I'd seen were unisex so I was wondering when/if the female gear would show up. So "Greed only" would indeed put everyone on the same playing field.

Thanks for the responses everyone, but Neri and Bixillarla hit on the one thing I hadn't thought of that makes this make sense to me.

[Alberel]

There are also items that cannot be needed if you are of different gender, like those Thavnairian series that can only be needed by female.

This is the primary reason for groups using 'greed only' instead of 'all need' in aquapolis.

Any other reason is just force of habit.