I think in this case forcibly ejecting the injured ant could lead to more injuries of otherwise healthy ants.
[1]: https://www.sciencedirect.com/science/article/pii/S096098220...
Wonder if this has something to do due with space constraints. If the study was done in a controlled nest, it must be space bounded one way or another. Dynamics might change when in real-world?
Eusocial Security?
The ants love one another, as shown by their child-rearing, grooming, playing, the "antennating" mentioned in the article, collective defense, and deliberate handling of their dead.
We don't understand their language, but I have a certain faith that ants experience a very similar kinship for their sisters as we. If they were strictly-rational robots then why would they show these behaviors?
So there are serious people who think if the chimps(or any social species for that matter) ever survive 200 million years borrowing ant like behavior at individual and group level is a possible way.
I remember when I was much younger I got cancer. The same cancer Hank Green had more recently if you want a relateable celebrity example. It's fixable, and I live in a country with universal healthcare, so of course they fixed it. Even if you care only about simple economics that's a sound investment. I was already a massive net cost, needing feeding and care for decades before I became an adult able to do something useful and then almost immediately (in fact, technically before getting my first "real" job) getting cancer. If you do nothing the cancer kills me, we can't prove it's fatal because we figured out how to cure it† before modern scientific medicine and it would be unethical to study that on real volunteers now, but we can observe that crazy people who insist "No" when offered a cure today do die, horribly, as you'd expect if it's deadly.
But under universal healthcare of course you fix people like me, we become ordinary productive citizens and contribute to society including by paying some eyewatering amount of taxes over the subsequent years, which helps pay for said universal healthcare.
Many cases aren't like mine, but we forget that quite a lot are, and without universal healthcare you are net losing money so as to hurt poor people which is full-on "Capitalism is a death cult" insanity.
† Some people will tell you cancer can't be "cured". Well, OK, the doctors who treated me do this all day every day, they'd never had a young man die of this cancer. They'd had some close calls, some old men die of this cancer, and they'd had plenty of young men die from other cancers under their care, but this one, nope. There are technical reasons, but they're boring and Hank Green probably made a better video explaining them than I could.
I think you're wrong, and its painfully obvious that ants do indeed form a bond with their community. The proof is in the system.
It can be both, right? To the best of our knowledge, they are not likely to have complex emotions. We cannot test it due to physical and technological limitations.
You can argue the other way but "proof is in the system" is not a very sound one.