If you're not familiar with the nursery rhyme: after Humpty Dumpty falls off the wall, you get the two lines
All the king's horses and all the king's men
Couldn't put Humpty together again
But what do the horses have to do with anything? Talking about the king's healers/medics would make sense, but why mention the horses whatsoever?
Normally, I'd dismiss it as some throwaway nursery line that doesn't mean anything, but in Zack Snyder's cut of the Justice League, Part 5 is named "All the King's horses", leading me to believe that there is some actual meaning there.
If I had to guess: the point is the irrelevance. The King can afford a zillion things, such as horses, but those can't save his people. Is that about right?