There are arguments to be made on both sides of this issue.
On the one hand, you can argue that societies should not allow people to be poor if they (the societies) have the means to prevent it. This would especially be true for older people who presumably worked all their lives and who cannot reasonably be expected to go out and get a job to fend for themselves.
On the other hand, the other argument says if society guarantees care for such people, it will be promoting moral hazard. In other words, it will be protecting people from the consequences of their own bad decisions. This will make people more likely to make bad decisions. After all, why should I scrimp and save for my retirement if I can simply retire and have the government take care of me? From this point of view, people should be responsible for their own actions. If they fail to save, they must bear the consequences, perhaps seeking help from family members to get by in their retirement.