I think that Li was either misinformed or ducking your question. Generally, one of the rights an exclusive licensee has is the right to enforce its exclusivity against third parties. The exclusive license is worthless if only the licensor can enforce it but chooses not to do so. Unless there are explicit provisions in a contract stating otherwise, generally either the licensee or the licensor may try to stop infringement by a third party.
In this case, I do not recall anything specific in the Parallel Licensing Agreement of the MTA requiring or prohibiting LQMT from trying to stop a third party from infringing. Li might be ducking for a couple of reasons: (1) the litigation can be expensive and LQMT doesn't see a financial upside to enforcing in China; (2) Li might not want to risk litigation where some patents might be declared invalid/unenforcable by the Chinese courts (such litigation might negatively impact the corresponding patents in the US).