I am not Japanese and I do not speak with authority on how Japanese people think or feel, but this is a conversation I have had with Japanese people, friends of Japanese descent, and with people who live or have lived in Japan personally. I cannot claim personal or objective knowledge on the Japanese experience but this is my understanding and my opinion as informed by conversations with people who can.
Straight up, comments like "because Japan" are modern Orientalism. It is non-Japanese people using a falsely inferred Japanese identity to defend their favorite products. They are not defending Japanese sensibilities when they make this defense, they are defending their own.
Japanese people hate this. People of Japanese descent hate this too. Imagine people making judgments on your entire culture based on the limited amount of media that is exported to them. Imagine that most of these products are pornography, cartoons, or video games meant for specific subsections of your population. Imagine people feel like they understand Japan and its "sensitivities" because they have played every Persona game. These people are real. They're the same people who accuse you of Imperialism when you say "this game should have less homophobia."
There are women in Japan. There are gay people in Japan. There are trans people in Japan. Japanese people in these groups are just as badly affected by mainstream prejudice and bigotry in their culture as people are elsewhere in the world. The argument that these things are not important to Japanese people, or are "not a problem in Japan" is wrong. You are not supposed to object to prejudice because it offends your sensibilities. You are supposed to object to prejudice because it hurts people. Prejudice hurts people regardless of where it comes from.
When you say you should be more forgiving towards prejudice because it comes from Japan, you are indicating that the people in Japan who are hurt by this content don't matter. Only you, the international consumer, matters. And since you've decided intolerance is acceptable when it's Japanese, who cares about them?
These are the kinds of questions you need to ask yourself:
Do you think women in Japan who suffer discrimination, sexism, or abuse are looking at how they're portrayed in Japanese media and have no objections?
Do you think gay or lesbian people in Japan have no opinions on homophobia?
Do you think there are people no in Japan who find this same content distasteful?
The argument that this sort of content is more tolerable because it's Japanese in origin is a bad one. It straight up erases all the minorities or marginalized people in those countries by assuming they are not hurt by all the same material. It also describes Japanese people as universally tolerant of objectionable or hurtful content. It's attributing a universal cultural identity to Japan that does not exist.
Societal and cultural norms, patterns, and trends absolutely exist. There are countries all over the world with broad societal and cultural intolerances. But you have to stop defending oppression from the point of view of the oppressor. It is not okay that there are broad or prevalent intolerances anywhere in the world. Oppose it, and object to it, wherever you see it. Not just because of how it makes you feel, but because of how it affects the people who actually live there.
Edit: One more thing. International discussions like this suffer from a distinct lack of Japanese voices. It is almost always non-Japanese people attempting to interpret and draw conclusions based on a country they've never visited, a language they don't speak, and a culture they've never been part of. This is a big part of what feeds this issue. The language barrier keeps people like us from ever hearing actual Japanese opinions or perspectives so instead we just reinforce or dismantle the ones available to us. Those are rarely Japanese and that is unfortunate.
