Okay I'll explain.

Having a kid doesn't mean your kid or its kids are going to end up in shelters, on the street, or killed because no one will take them. There is also a fairly low rate of production among humans, especially in first world counties. On top of that people can take care of a few kids, and then those kids will be able to take care of their own kids, and so on.

Cats on the other hand breed excessively, most do end up in shelters, on the street, or killed because no one will take them. You MIGHT take care of 5 cats, like this person seems to be saying they will (I don't exactly believe them, but whatever) but they sure as shit aren't going to take care of another litter, or if those cats get a bit older and have kittens.

Those kittens will be able to reproduce at ~8 months old or so, and be able to produce 1-5+ kittens (usually bigger after the first) which only takes 3 or 4 months after conception. This means they have have 3 litters each year.

If you're acting like this owner is going to be in the lives of these cats, and their kittens, and their kittens kittens, or that he's going to take care of all of them, you're delusional at best, lying and trying to play "devils advocate" at worst, and honestly, I can't stand when people try to make these ridiculous arguments.

What do I care? I care a because this isn't something cats have just done. It's something humans continue to let happen for no reason what so ever. We really don't need to fill our streets and shelters with cats.

Don't even get me started on male cats, who can just run around impregnating everything they feel like.

On the other hand a human in a first world country generally has two kids in their entire lifetime, takes care of them, teaches them to take care of themselves, and then they grow up and are able to actually take care of themselves and participate in society. They generally do not end up in shelters or pounds, they aren't generally killed off, and it is generally something people are capable of handling.

So no, your comparison does not make sense, not really, and it's a ridiculous comparison. I personally think adoption is great, and it should be a question on peoples mind when they think about having children, but it's not even remotely the same as questioning of you should be spaying and neutering your pets.