eastern countries have varying levels of it. most are fine with couples, but they havent tied the relationship to the legal version of it.

Taiwan i think is the only region that outright performs it. Thailand is probably up next as they already have many rights in.(edit: they it it very recently) other countries like Cambodia, Japan and such have some rights to gay couples, but they arent entirely 1:1 to their hetero couples yet. The graph probably represents gay marriage being analogous to all rights offered to both types of couples in a binary fashion.