Well, if you are going to stay open for long, you had better not use rancid oil! Let's ignore that concern for now, as it generally applies to all food products.

"seed oil" -- What is this nonsense that I keep hearing about on social media? Literally, RFK Jr. (US Secretary of Health) says (amoung other crazy things) that seed oils are "poisoning Americans". Is there any peer-reviewed science behind this "seed oil is bad for you" movement? I have not seen it. Also, Japan uses a wide variety of cooking oil. Probably, olive oil is the least used (only in southern European restaurants). I guess that soybean, canola, peanut, cotton seed, rice bran, and sesame seed oil are the most common oils here -- pretty similar to most of the highly developed world (except rice bran and sesame seed).

Google tells me that soybean, canola, peanut, cotton seed, and sesame seed oil are all considered "seed oils".

"high and long temperatures on polyunsaturaded oils": Japan eats more fried food that people realise, but the portion size is quite small. As I understand, to fry food, you need to have a pool of it that is constantly heated to cooking temperature. That seems to qualify as "high and long temperatures". In fact, wouldn't all fried food suffer from the same? I don't understand the science behind this comment. Can you explain it to me like I'm five? (Other people may be interested to learn more.)

Final small thing: It is best to avoid the term "Japs" in English. It has a historical discriminatory meaning in the United States.