They are tying one market (phone hardware) to another (their messaging network). Whether that rises to the level of "abuse" is up to you.
I consider it so because of recent reports that 87% of US teens own iPhones, and colloquial knowledge of how "green bubbles" negatively affect teens' social and mental health.
That teens like iMessage and are dumb enough to cyber bully each other over it is not Apple's fault in the least. Their idiocy definitely does not constitute market abuse on Apple's part.
Green bubbles, plus making iPhone using friends and family too lazy to install a 3rd party messaging app (accusations not valid outside of the continental US).
How is Apple to blame for the laziness of your family and friends? I've never seen Apple disencourage in any way third party messaging apps on their devices.
