I seem to be noticing this more on certain anime facebook groups and the like where a pettanko (flat-chested female) character is shown with the tagline "Flat is Justice" often used as a rebuttal towards a more well endowed female. The meaning seems fairly clear and seems to be a rallying call for Loli style character fandom, but I've been unable to uncover an origin for this meme.
There also seems to be a sub-related meme where "Justice" (flat-chested girls) are pitted vs. "Plot" (busty girls)
If anyone could shed more light on this I would be grateful :-)