Here’s the thing — some people here seem to be conflating societal discrimination to legal recognition.
[Long Post incoming]
Gay Marriage may not be legal in Japan but there are other forms of financial/domestic cohabitation in the law. A marriage in everything but name as I understand it.
Japan legally is very much liberal in terms of LGBT+ Rights, by simple passivity, so overtime the younger generations are growing up and it’s becoming more normal. However it’s the same as saying the US isn’t transphobic because it allows trans people to still exist.
Japan doesn’t recognize non-binary, Conversion Therapy is still a thing there and the generational gap is easily one of the most extreme ones due to secular values clashing so hard with Japanese traditionalism.
You’d probably get favorable/tolerant responses from young people, but open-mindedness is not the norm for the voting majority there.
Got some of this just after a bit of research online. But a very handy site that simplifies/aggregates this is
The Equal Rights Index.
Not perfect, but gives a good idea about the legislator side.
Also another important point:
Fiction isn’t reality, know that may be silly but there are multiple comments using the argument that it can’t be homophobic because GL/BL are genres. As long as a country has freedoms in expressions, anything can be a genre.