My understanding is that many Western firms had willingly entered into business agreements with Chinese firms, primarily for manufacturing but also for access to the Chinese market. It was always understood that such agreements included technology transfer, even if that wasn't always communicated to e.g. shareholders of Western firms. Not all Western firms entered such agreements, but those who did can't very well start crying about "hacking" now. When you tell someone a way to make money, they're going to remember that.