Comment by microtonal

Would it have been wiser if that person had, as a US citizen, just refused to provide a PIN?

Purely technically it would also depend on the state of the phone. Phones can be read out/exploited more easily after first unlock (AFU) than before first unlock (BFU). So, a middle path would be putting the phone in BFU. Much harder to use exploits against the phone and biometric authentication doesn't work. One way of fairly reliably doing this is setting the reboot timer to 10 minutes or turning off the phone in critical situations.

It's also relevant to take into account that he wasn't protecting himself by wiping the phone, but fellow activists. So, he may have taken the risk of potential legal issues by wiping the phone to project others.