DOJ is correct that Apple iPhone is far less secure than Android when RCS messaging is involved

This is the common misunderstanding with both RCS in general and Apple's
update in particular. RCS is not end-to-end encrypted.

Yet, for conversations between Google Messages users, end-to-end encryption
is now enabled on your Android phone by default.
https://www.forbes.com/sites/zakdoffman/2024/03/30/new-apple-iphone-16-pro-max-and-ios-18-leak-googles-imessage-warning/

So unlike iMessaging between iPhone users or Google Messaging between
Android users, or more importantly WhatsApping between iPhone and Android
users, RCS between iPhone and Android will not have that level of security.

This is critical because it's the issue the DOJ highlighted in its lawsuit:
"Apple is willing to make the iPhone less secure and less private... Text
messages sent from iPhones to Android phones are unencrypted as a result of
Apple's conduct. If Apple wanted to, Apple could allow iPhone users to send
encrypted messages to Android users while still using iMessage on their
iPhone, which would instantly improve the privacy and security of iPhone
and other smartphone users."