I do believe you should, and I genuinely believe that one person can make a difference by being kind. However, in practice it's quite a challenging task to be consistent in. Especially when others can't seem to give you the same kindness that you give them. But keeping to your belief and keep practicing meta kindness and you'll find it's much better than the alternative of hating all of mankind around you.
Just do the right thing, the rest doesn't matter.
Also don't focus on the worst things people do all over the world, nowadays we receive so much information from every corner in the world. There's simply no way we could a) keep up with it or b) fix everything. So instead, focus on your immediate surroundings and the people in it. Treat these people with love even when they do bad. You never know what kind of positive ripple effect his might create.
Title prompts are taken from The Daily Stoic Journal by Ryan Holiday and Stephen Hanselman.