But Japan was never actually "enemy". Even with a closed economy, it took Japan much further development to become a "threat". On the other side of the coin, the globalized economy was only being built then. By the time Ren started using an iPhone, the WTO had been established for many years, and China had been admitted. A closed economy, such as Japan's would not be possible. Moreover, every Apple product was being produced in China, and by using Apple, he can get a strong feel for what he's up against.
On the other hand, this could all be bullshit, Ren saying "we are so open, and yet they're trying to screw us". Who knows about this, but either way, Huawei is about the best prepared in China, among the electronics companies, particularly those focusing on the consumer market. And note that the electronics industry is one of the most open ones in China, hence most vulnerable. They would not be able to hurt Chinese companies in other sectors in the same way.