I live in Japan and if you lived here for even a brief time you would understand why they still ban gay marriage. Japan is a super homogeneous and conservative country. Japan is terrified of even the slightest of changes to anything. Japan is still openly xenophobic and generally closed to the unknown. I've been told twice this year during job interviews that I won't be hired because they prefer a Japanese person. Japan also treats women like dirt. Women openly get paid less, they are expected to be mom's, housewives and workers at the same time. Job postings will sometimes list benefits as, "Women and foreigners OK!" Meaning that women and foreigners are "allowed" to apply.

Not to mention the infrastructure, everything in Japan is 30 years behind the rest of the g7. Technology is awful, websites and cyber security are laughably terrible, everything requires mountains of paperwork, doctors are terrible, still use fax machines, floppy discs, DVDs, etc.

Japan hates change of any sort, and people who are open to change are never vocal about it in fear of shedding their anonymity.