macOS allows argc == 0, it has a separate mechanism for providing the exec path of the executable to the process, namely the KERN_PROCARGS2 sysctl which include

macOS allows argc == 0, it has a separate mechanism for providing the exec path of the executable to the process, namely the KERN_PROCARGS2 sysctl which includes the saved exec path along with argc, argv, envp, and the apple pointer. Amusingly enough, Apple has had a bug in their `ps` since 10.3 that assumes argc > 0, which actually results in a similar (but not likely harmful, despite ps being setuid) bug.