Does bash explicitly allow commands like passwd, su, etc., to run in setuid while disabling other custom binaries?

Question

I know that /bin/bash has certain built-in protections that prevent the abuse of the Set-UID mechanism. So if I create a custom binary and execute it, it won't run with SUID 0 (refer the below image). Then how does running passwd in bash shell runs with root privilege?

C code of system file in the above image:

#include <stdlib.h>
int main() {
    system("ls");
}