The last 150 years of Germany have...ahem...not been what I would call "fine."
It would be interesting to have a replay of history without this law and similar ones related to it. Could be nothing different happens.
On the other hand, any law regulating speech is going to have a reverberating effect on the marketplace of ideas with 2nd and 3rd order outcomes that are impossible to disentangle after the fact.
But it's certainly not been because of that law…
At the very least I'm sure you'll agree we've been fine the last 80 or so years. Again, I'm just saying I don't understand the outrage right now.