It doesn't seem like the suggestion would be to destroy cultural landmarks, or even the majority of commercial ones, just the key components of the island's chipmaking industry that would incentivize an invasion by mainland China. It's an outcome that no one wants, but remains sufficiently feasible so as to be effective in preventing such an invasion in the first place. If the current CCP is bad, one that directly controls the majority of the world's chipmaking industry would be far worse.