Who seriously want to be friend with such iPhone-using person? In this sense, I would be proud to be left out.
In particular, because chats with green are functionally different from imessage chats, it gives bullies an easy out for social exclusion.
The wise decision is to leave people like this and not befriend them, but children don't know that, and few parents do either. And lastly, there is evidence that show bullies succeed more at life at the expense of those they bully [1]. It gives ammunition to the people who are willing to use something as simple as color to discriminate in communication channels. The small weasly design decision, which might have been to bring more revenue to apple, empowers the kind of people who have no sense of empathy or live life selfishly disregardingly destroying the people and the world they live in.
[1] https://www.fastcompany.com/3037427/why-the-office-bully-is-...
Or to put it into different words: if you are somewhat smart, you should see very fast that the only winning move is not to play.
It's not just one person sometimes, it may be everyone they know.