Because one of the methods reported was scanning http packets. Easily read without ssl from any hop in the chain. More importantly, he blew the lid off the fact that governments had access to this via the very ISP’s everyone relies on for telecom. By making everything TLS, they can look all they want but they can’t read it.
You could do tls offloading at your load balancer but then you have to secure your entire network starting with your isp. For some workloads, this is fine, you aren’t dealing with super sensitive data. For others, you are violating compliance.