[kayodelycaon]

Okay, there is a major definition problem here.

Kindness can and should come with boundaries. No one is entitled to your time or energy. Choosing to spend that energy on another person, without thought of reward, is a form of kindness.

We can and probably should be polite to people by default. That is a way of showing kindness. If the other person decides to be a blackhole, leave them. If they are harming someone, you are free to (and probably should) warn other people.

Kindness does not require you let people take advantage of you.