It just seems strange that the soldiers should be returning from a war in such high spirits, never addressing injuries, wounds, or possible deaths. This does make the scene rather unrealistic, but for the play to remain a comedy, it must be so. In contrast to the battle that has just taken place, there is a continuing battle of wits between Beatrice and Benedick throughout the play. Shakespeare is showing man's natural tendency to compete and win. Yet, there doesn't always have to be a bad and a good, a right and a wrong such as with Don Pedro and his brother Don John.
Humans just compete to prove their own competency.
Much Ado About Nothing seems to be a play about the power of words and the proper use of words. Words control the play by causing all of the action. The words make this play a comedy by balancing words which cause harmful actions with language which repairs this harm. The words of Don Pedro, Leanato, Claudio, Ursula, and Hero cause Beatrice and Benedick to fall in love, and their own words to each other, in the form of poetry and conversations, help them to reconcile their differences and marry. Similarly, the words of wooing which Don Pedro offers to Hero, on behalf of Claudio, win her affections.