Cats understand human kindness. We don't need studies to know this is true. Just look for one moment, and you will see it too. There is a reason that cats domesticated themselves. We didn't need to put in the effort like we did with wolves, for example. Cats just realized that humans really like fluffy small things, and they decided to make the best out of it. And all that we ask in return for feeding them and loving them and giving hem them homes is… nothing. We do it because we love it.
That's why we feed stray cats and feral cats too. We don't expect them to give us anything. Allowing us to pet them once in our lives would be all the payment that we could ever hope for. But they still like us, even if they don't let us pet them. We just hope they will. We hope they will bond with us. And we believe that if we stay patient enough… the cat will show us they love us. Even if it'll happen in some really unexpected ways.