It seems childish, but if you ever witnessed a bully use a small thing like chat color as a form of discrimination, you would realize even little decisions like this have huge implications on social development. We might not know what the original intent for chat color is but the reality is, believe it or not, wether you want to admit it or not, something as simple as the color of a chat bubble reaches way farther than anyone probably is willing to admit and likely will make a noticeable difference in the future grades and income and social standing of a child.

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-...