I believe this military exercise is a response by the PRC to the inauguration speech by Lai. Lai essentially stated that the PRC-controlled mainland and ROC-controlled Taiwan are both sovereign, whereas the previous Taiwan president, Tsai, from the same party, used more ambiguous language regarding sovereignty and only emphasized governance (Yes, there are a lot of nuances in the wording of this relationship). This statement can be construed as an attempt to change the status quo. (We are referring to a third-party definition of the status quo, because the official PRC stance is that Taiwan is part of China, so even taking Taiwan by force is not considered a change of the status quo.) The PRC likely waited to see Lai's speech, checked if it aligned with Tsai's rhetoric, and prepared a response accordingly.<p>I think Lai's speech was not the most extreme because it contained little mention of "democracy vs. autocracy," which is something even the current US administration would find provocative. However, this speech would still warrant a response from the PRC, at least from the perspective of internal PR, because it differs from Tsai's approach, and they cannot let it go unnoticed.