Didn't know that but it's funny that receiving a green message bothers those other family members lol. Pretty dumb.
Its not just the color bubble. If you have a group message thread going with a bunch of iPhones, and one non-iPhone enters the thread, then any video or picture sent by ANYONE in the thread will be degraded to near unusable quality. I only really do group messaging with my family and we just use GroupMe. But imagine you are a mother of a couple of school age kids, and are in dozens of group chats with other moms, and most of them have iPhones. You end up screwing things up for all the rest. That's not an easy pill to swallow, and in the US it is forcing the competition out.