A "free kittens" sign can mean a few things, and they are generally never good. It could be that someone's cat had an unexpected litter, and they were lost as to what to do with all the kittens. It could mean that a stray cat gave birth on someone's property, and they didn't want any of the cats. It could mean that the expected litter was bigger than the humans were ready to deal with. Either way, the kittens are not wanted, and the people who have them are willing to give them to anyone who's willing to take them. No vetting, no questions, not even a small fee. And if kittens are not wanted, then these kittens will - at best - not be cared for, and at worst, they will be thrown out into the street. If you are someone who loves cats, then the moment you see a sign like that, your hackles should go up.
Thankfully, the couple who crossed this "free kittens" sign realized that something was off about it. And when they got there, they saw that the situation was a lot worse than they expected. They notified the authorities, but as it is with bureaucracy, it was going to take them a while to do something about it. And this couple couldn't wait. One kitten looked bad enough that they could not simply leave it, and since the hoarder wouldn't let the kitten go, the couple… snatched it. And it's a good thing they did. The time that this kitten had left in this world was short, but it was spent with nothing but love.