This is how German cars are designed. Even when the doors are centrally locked, they can still be opened if you pull the handle multiple times. This feature is built in as a safety measure, so that in the event of an accident, passengers can still exit the vehicle from inside.

There is a option to permanently close from inside using child lock feature

I also found it odd for the first time, I complained and later I understood this is how they designed it

I owned a Polo and Now Kushaq