The word for weak is a general one referring to any lack of strength. It can refer to the physically weak, the psychologically weak, the spiritually weak, the morally weak. Even as read those phrases it is worth noticing our internal response. How do we feel about each group?
The fact is we don't like weakness of any kind. We would rather be thought of as sick than weak. Why? Because we think weakness is your own fault, as if a person can simply choose to be strong. We like to tell ourselves the lie that with enough effort anyone can go from weak to strong. "Pull yourself up by your own boot straps", as the old folks used to say.
Have you ever stopped to notice how much longer it takes a human baby to become able to care for itself than animals? The word Pope Francis uses over and over again to describe us is "fragile." Human being are very fragile compared to other creatures. And it doesn't appear to be a flaw. It's how we were made.
Our weakness, our fragility is not something to be ashamed of; its part of what it means to be human. It forces us to depend on one another, and most of all it calls us to depend on God. God calls us to depend on him, but never forces. The choice is always ours.
Perhaps if we could acknowledge our own weaknesses, then we could be more empathetic toward the weaknesses of others, and help them as St. Paul tells us we must rather than simply blame them as we so often do.