Kindness matters. Because how you choose to act, affects the headspace that you surruound yourself in. When you judge others, your own experience of living is filled with such judgement. When you hate, then you experience hate.
So for purely selfish reasons, why not choose to be kind? Being immersed in positivity, gracefulness, and space are good things. Choose to live out kindness, if only so that your personal experience of life is less hateful.