The main thing so many people on this site fail to realize is that the manga is not marketed towards us, unless you are a Japanese that is. Every isekai manga without fail you would find comments about why the MC has to spread Japanese culture, why he prefers katana or inaccuracies about history, etc. The fact that there are so many isekai copies that used this template, it should be easy to conclude that this method of writing works for the Japanese audience that they are targeting. Isekai is largely about escaping reality, escaping real world, given how hectic and stressful the Japanese society and worklife is. And for people who wants to read these works to escape reality, do you think they care about the details whether your pottery exist in who knows what age or how this method of farming existed way before? Japanese culture is prevalent in the story simply because its a Japanese author writing for a Japanese audience, it would be easier to self-insert into a story with familiar elements to your daily life. People should just stick to discussing the quality of the art or story in terms of criticism.