They did not fight, tens against thousands; they did not fight for wives and children, but for lands and plunder: therefore they are heroes!
The mark of exclamation keeps up the semblance of seriousness which is of the essence of irony.
XXXVII. The mark of exclamation is placed after the statement of some absurdity.
He has been labouring to prove that Shakespeare's plays were written by Bacon!
To him the parliamentary vote was a panacea for all human ills, and the ballot-box an object as sacred as the Holy Grail to a knight of the Round Table!
The same reason applies to its use after such sentences as after ironical statements.
XXXVIII. The mark of exclamation may be placed after any impressive or striking thought.
The Angel of Death has been abroad throughout the land: you may almost hear the very beating of his wings!
It may be doubted whether the mark of exclamation is in such cases of any great service; for the impressiveness of a sentence ought to appear in the sentence itself, or to be given to it by the context. There is a real danger, as the style of many people shows, in thinking that punctuation is intended to save the trouble of careful composition. In putting the mark after pure exclamations, usage is more or less uniform; with regard to impressive sentences, we are left entirely to our own discretion.
XXXIX. When a sentence contains more than one exclamation, sometimes the mark of exclamation is placed only after the last, sometimes it is placed after each of them, the test being whether or not they are in reality, as well as in form, several exclamations. (Compare [Rule XXXI.])