re: Please explain to me
The signers were aware that Britain's response to the Declaration was not going to result in a peaceful outcome.
Had "peace" been their only goal, toleration of British abuses would have avoided the full Revolutionary War.
Had Lincoln simply given in and let the South secede peacefully, hundreds of thousands of lives would have been saved that were lost in the American Civil War.
"Peace" is a very fuzzy word. It needs a lot of clarification when it's used.