This seems odd to me.
The main risk to Taiwanese fabs is a Chinese invasion ( and either Chinese bombing or American bombing of Taiwanese fabs to prevent them falling into Chinese hands ). The chances of Japan getting dragged into such a war are non-zero. If Japan and China found themselves on opposing sides of a shooting war, China would do its best to destroy Japanese fabs.
Surely the potential upside to having a fab outside the far-east far outweighs the potential extra costs?
Can anybody explain why this basket of eggs is being placed right next to the existing basket of eggs - right under the massive ACME anvil?