He was a Union officer and to him the request was unpatriotic and he was being asked to give up on everything he believed in. To his Mother it seemed to be compromise out of love for her child. I think many of those southern Democrats living in the northern states felt the same way as she did even if for different reasons, seen through different eyes. To them it was a simple request for compromise that might lead to keeping the Union whole without 4 years of Americans killing Americans. Personally I think the author explained the situation quite well.
Few Northerners, whether Democrats or Republicans, spoke out openly against the Civil War during the spring and summer months of 1861. The Fort Sumter affair, the firing on the U.S. flag released a wave of patriotic fervor. War meetings whipped up emotions, flags flew on every hand, and President Lincoln's call for troops met a glorious response. The Cincinnati Enquirer, voice of area Democrats, gave a qualified endorsement of the war. Only the bold heart dared call for compromise or put the blame for the war upon President Lincoln and the Republican party. "I am not deceived in my faith in the North," an observer in Washington, D.C., wrote: "the excitement, the wrath is terrible. Party lines burn, dissolved by the excitement. Now the people is fusion, as bronze." Patriotism seemed to have triumphed over partyism as a member of Lincoln's cabinet wrote, "The Democrats generally as well as the Republicans are offering themselves to the country." The patriotic surge, so strong during the early months of the war, ebbed as time tempered the emotions and reality made its presence felt.
On the other hand, President Lincoln's surrender to pressure from the abolitionists also contributed to the widespread dissatisfaction with the war. Democrats who supported the president when he revoked General John C. Fremont's proclamation of August 30, 1861, and annulled General David Hunter's directive freeing the slaves within his department, turned against him when he gave support to emancipation policy—they considered the Emancipation Proclamation of January 1, 1863, to be the last straw. The Cincinnati Enquirer, which had given Lincoln and the war qualified support until he issued his two proclamations of emancipation, turned upon the president like a mad dog. Democrats argued that emancipation was unconstitutional, impractical, and unnecessary; they argued that it violated Lincoln's inaugural pledge as well as the Congressional resolutions defining the objectives of the war. They added that emancipation would discourage enlistments, unite the South to a man, dampen support of the war in the North, and make compromise and reunion nigh impossible.
Sound and Fury: Civil War Dissent in the Cincinnati Area by Frank L. Klement