It’s a little thing, so very little, but it matters. One small factor among many that allow the iPhone to sustain higher prices and margins.
Yes, if you have an iPhone and send an iMessage to someone else who has an iPhone, you see a blue bubble. If it goes to a friend without an iPhone, it is a green bubble.
But Apple did not do this on purpose to get people yo hate Android. Any text message (usually SMS) that does not go through the security of iMessage is green. It is not simply an Android thing.
And, more importantly, the green bubble was present BEFORE iMessage existed.Yes, everyone used to be in a green bubble until Apple created its own messaging service. So, it kept green for SMS messaging, the same color it had always been, and chose blue for its own messages.
Why a different color? Cost for one thing as iMessages do not cost anything. And security for another. Point-to-point encryption.
As well as no 160 character limit. And all sorts of emojis. Easy to send pictures. The experience is much better because Apple provided specific interface improvements since it controls the servers. SMS is generic because it is used for everything else.
The hate for green bubbles came from the people using iOS. I’m sure Apple is not unhappy with this. But to say that the green was chosen simply to go after Android is ahistorical. This is simply a made up, stupid tempest in a tea pot.