As people are interpreted to be "mean" and/or acting against the "kind" it is because they are seeking attention, because not enough people in their life have actually "listened" to them and/or demonstrated a true, honest interest in them.
Rarely is there such a thing as someone who is "mean" 24/7/365 throughout their life. So, being mean is a reaction to something or the lack-of-something in their life. Either in the past and/or currently.
"Mean" actions mean the lacking in ability to truly love one self, and in turn the great struggle to act loving (kind) towards others. This may be incrementally or more continuous in the perception of others.