Hello Olivier,
Just replace the term "filter" with "selection" in your head. Maybe it will be clearer then.
It's like the check and search window. You deselect what you don't want to see.
In the logbook, too, the active filter deselects what you don't want to see.
For me, this is the case with filters in many programmes where you can make a multiple selection when filtering. All that is selected is also displayed, otherwise no meaningful multiple selection would be possible.
Regards
Markus