How can you be kind to someone who takes advantage of your kindness? who exploits you? who manipulates you? who gaslight you? who gives you silent treatment?
I think kindness is great but you need to be more cautious as well - you should know what your boundary is. If not, over and over again you will be used like an object.
You should always maintain balance, and whatever you give towards universe, it returns to you like a butterfly effect. So yes kindness and in case of exploitation, forgiveness pays you back in longer run