the credit freeze is ONLY affective where a credit report is needed to approve an account. Identity theft victims though are more frequently hit by utility fraud, telecommunications fraud, medical fraud, criminal fraud and other types of synthetic id theft where a credit report probably will not be accessed. without the credit report being accessed, the credit freeze is useless.
In order to establish accounts with telecommunications and utility companies, they will perform credit checks.
As for medical fraud, you are correct...freezing credit will do nothing.