I think the answer is rather simple. Free will and the ability to choose good cannot occur unless the opposite of those things exists and can be understood.
There is no happiness without sadness.
No health without disease.
No compassion without suffering.
Me mercy without justice.
No love without hate.
No life without death.
I disagree with the premise of your post.
I believe there is indeed happiness without sadness. At least ultimately, in heaven. There is no sorrow there. Yet everyone is joyful.
If, by your statements, you mean to say that bad things are definitely going to happen in this world, then yes, I agree.
I like to see laws that minimize risks to others, without making life so risk-free as to be unliveable.
As an example, we require hotels have guards on their windows so that kids and stumblers don’t fall out.
But we don’t forbid them to have windows at all, nor do we require them to check them every hour on the hour.
There is a middle ground, and I think I am advocating that.
Actually my reply wandered off into a tangent, sorry. Wish we had the ability to delete our own posts. I’d have liked to clean my reply up somewhat.