Yet the article literally says it does:RCS is not secure it has no encryption by default and if the carrier does not support it or its not enabled on the phone it goes no where.
"It provides support for higher resolution photos and videos, audio messages, and bigger file sizes, plus it adds improved encryption, cross-platform emoji reactions, and more reliable group chats across different devices. Google has been pushing Apple to adopt RCS for well over a year now, but so far, Apple is not budging."