Apple has customers who want to use iMessage. Those customers are not able to use iMessage to securely communicate with Android users.
That's pretty clear. If Apple's customers want to be able to use iMessage for such communications then (1) the Android user buys an Apple product, (2) a third party makes a cross-platform iMessage client, or (3) Apple open iMessage to other platforms.
That's pretty clear. If Apple's customers want to be able to use iMessage for such communications then (1) the Android user buys an Apple product, (2) a third party makes a cross-platform iMessage client, or (3) Apple open iMessage to other platforms.
Apple is blocking on (2) and (3).