I would imagine because "two wrongs don't make a right" and because "doing like the others" validates their doing.
Giving up the moral high ground is not a move of a superpower, and aides in destabilising the geopolitical playing field.
Giving up the moral high ground is not a move of a superpower, and aides in destabilising the geopolitical playing field.
At the core of it, the kind of protectionism China has engaged in is defecting in a prisoner's dilemma. If you play always cooperate against a defectbot, you're going to lose eventually, even if you start very far ahead.