In Jonathan Swift's essay entitled A Modest Proposal, I believe that since the rest of this satire was harsh and outrageous (the darkly satirical idea of eating babies sold to rich people so the poor could survive without resorting to prostitution, thievery, etc.), it probably seemed appropriate to him to point out what an outlandish point he was trying to make—by sarcastically terming it a "modest" proposal...when in fact, it was gargantuan!
His terse mock-treatise A Modest Proposal is considered the most brilliant short prose satire in the English language.
Swift's concern, of course, was to do something about the terrible state of affairs in Ireland that he had witnessed first hand. However, those who are financially secure may not always (or ever) wish to show concern for the the hardships of others. It's not their "revolution." Of course, the title probably did not find significance with the audience until readers understood what Swift was "proposing" because he started the essay out quietly, with control and "gentle concern."
The essay begins innocently by establishing the speaker as a concerned citizen genuinely sympathetic to the Irish poor...
Once Swift gets into the "meat" (pardon the pun) of his argument, the title takes on new meaning.
The modest proposal is of course anything but modest: It is savage, frightening, perhaps even insane.
However, none of it means anything if the audience which it was directed do not get the point. The Irish continued to suffer, and it was something that greatest troubled the civic-minded Swift.