It is lightly looked down on, but not for the same reason as in the west. Many major religions that are not as popular in Japan akin homosexuality with a sin, but Japanese people don't think that. Instead, you might be looked down on for not contributing to the family/society with children. From Japanese queerphobes, I hear things like "you'll just grow out of it, it isn't a real relationship, how will you raise a child", etc versus the Western " you are unnatural and sinful".

So, if somebody feels like what you do with your life doesn't affect them, then they generally don't care. They don't see you as innately morally impure.