It works for me, you just probably don't know how it works.
If you add multiple lines of the same filter, they will be in logical OR connection, so all replays will be included where one of the same filter-type applies.
The different filter rows are in logical AND connection, so if you specify the player filter and the map filter, both have to match for a replay to be listed in the result.
So back to the player filter, if you specify one with player="Bob" and another with NOT player="Alice", all replays will be included where there is a Bob player OR if there is no Alice player in the replay.