If you're editing /etc/ssl/cert.pem yourself, you're setting yourself up for failure. Use the proper mechanism to add your own trust roots (on macos it's "security add-trusted-cert").
Whatever reason Apple had for not updating /etc/ssl/cert.pem yet, I am certain it's not out of consideration for users that might have put custom certs in there.
Whatever reason Apple had for not updating /etc/ssl/cert.pem yet, I am certain it's not out of consideration for users that might have put custom certs in there.