[keycloak-user] authz client incompatible with client definition

I am writing a command line interface which needs to authenticate against keycloak. After creating the client definition in keycloaks admin console i copy the installation data (keycloak.json) into the cli. When i try to use the authz client i am not even able to create the client because it does not know the option "ssl-required". When i remove this option the client can be created but throws another exception when i call "obtainAccessToken", this time complaining about missing credentials. The credentials are missing because i made the client "public". Am i doing something wrong or do i missunderstand the purpose of the authz client?