Hello,
I already had to add some unsafe-eval to allow some third party scripts.
I don't have any real explanations to give you, but perhaps some logic.
You need to execute some scripts from a third party service in your code, otherwise it doesn't work. If you have chosen this service, that means that your trust this service. So you can allow this script to run in your application.
But you should accept ONLY the script itself and not the entire domain name where is the script. This way no other script will be able to run in your application, even coming from the same domain name.
If you really don't want such a situation, you can download the script and host it in your own server.
I hope it will help you ;).