It's not a very thorough test compared to many of the others. I would guess because PostgreSQL doesn't support multi-master clustering.

However, in the test that was done, PostgreSQL did not lose data. The failure mode was that transactions were committed without the client being notified. Kind of the opposite of data loss - there is data in the database that the client doesn't know about.

I believe you can use prepared transactios and some client smarts to mitigate this depending on your use case . There is some back and forth for sure, and the risk of locking the database is higher.