Part of the Unix philosophy is "trust the user". So for the tiny minority that uses a DBMS without some kind of distribution-supplied init script that usually handles the privilege dropping, I don't see why running as root should be forbidden. In any case though that's a very minor point and can hardly count the same as ACID support with which, for many people, database systems stand and fall.

You have to click "see more" under "Features" to see that PostgreSQL is supposedly not OSS. There you can also learn similar wisdom such as that Mariadb can neither import nor export data, Postgres has no "Internet Protocol Support" and MariaDB has multithreading but no parallel processing while for Postgres it's the opposite.

I completely agree with the general conclusion that Postgres is a superior system for many applications, it's just that this list is a collection of bullshit that just happens to come to the same result. It could easily reach the opposite conclusion given how many errors and apples-vs.-oranges it contains.