Meanings of Message Rating Icons

[The People]

Curious as to why the use of icons is n longer mandatory. At times I understand that it doesn't matter except for the people involved, like when there is a flower or hug. But red dot or triangles, especially the red ones. I know it is encouraged and I still do it automatically but when I first came and was not ready to deal with yet undiscovered red dot issues, having the sign up helped me to avoid them.