The two situations are nowhere near similar in that caring for a small animal takes nowhere near the resources of caring for a human being who has free will.
I'm not really seeing the relevance here.
People who feed stray animals of any type without the intent of somehow finding them a home or even bringing them into theirs are just being selfish. They get to feel better about themselves or assuage their guilt without taking any real responsibility for the well-being of the animal.
...you do realise this is pure Nirvana fallacy right? "If you can't do something about the impossibly large big picture you shouldn't do such small things you're capable of either" which is bullshit reasoning and basically just an excuse to do nothing.
Also nice arbitrary assumptions of other peoples' motives.
A human being has the free will to determine whether they want a better life, and the motivation (or not) to make it happen. Getting help from people is great, and encouraged, but it is ultimately THEIR responsibility. An animal cannot make that choice, especially if it didn't grow up having to scavenge for food or learn to hunt. That is why it's relevant.
Also, I don't care what fallacy you want to attribute to it, it doesn't change the fact that not taking the time out of your life to even try to find a home for an animal that is without one and just giving it some food is a selfish act to make you feel better about yourself. There is no "impossibly large big picture." You either help, or you decide not to. Feeding an animal reinforces its dependence on people, and unless you plan to always go and feed that animal, there isn't a point. You're prolonging its suffering, and you might as well have used the time you spent giving it food to find it a home. I've never found a stray animal and simply given it some food and left. Every single time, I've either found its owner, found it a home, or given it to our local no-kill shelter. Acting like people aren't capable of doing something so small but meaningful is what's the real bullshit.