Yeah, I guess compared to the demimonde of 1920s Berlin one could say it's pretty tame.
But by that, and the other indications you are providing - "some are intimidating, some not... you can even walk safely at night if you stick to the large paths" are what I mean by falling fall short of the standards of what one expects from nice, decent and inviting city park.
As for the kids and families there during the day - it's not like they have much choice.
Where you from?
Let's just say I've lived in plenty of places in Europe - not necessarily 24-hour party people destinations like Berlin, but definitely not backwaters either - where one didn't have to think twice about taking a walk in the park at night.
I also remember a Berlin from not too long ago when it was ugly and decrepit (if in a beautiful way), for sure - but where one didn't need to be on one's guard in so many places, as now.