It's nothing new. Chinese companies (mainland and Taiwan) have always courted "returnees" and "foreign experts" to develop their own capabilities.

Famous case in point is the very founder of TSMC, Morris Chang, who was convinced to move to Taiwan from the US to lead a research institute, which ultimately led to him starting TSMC.

Of course, as criticality increases so does the number of zeroes on the offer.

How is this different than a US or European based company hiring someone with a high degree of knowledge from another US or European country?

What makes this more of a ethical violation because a national order was crossed?