President Lincoln was not pressured by northern abolitionists to issue the Emancipation Proclamation. Practitioners of abolitionism represented too small a percentage of the population to carry such political sway, however, antislavery proponents did.
The Antislavery Movement comprised northern politicians and leaders who were concerned about the growing political power held by slave states. Its supporters were not concerned with the plight of enslaved Africans, and did not accept them human equals, a major concept of abolitionism. Famous and outspoken white people, like Ralph Waldo Emerson, Henry David Thoreau, and William Lloyd Garrison, used their respective platforms to protest and rally others to their cause, but were ineffectual politically.
No war is fought for one reason, but a major cause of the Civil War was the conflict between slave states, mostly in the south, and free states, mostly in the north. When western territories were being admitted to the Union, the controversy was mainly about which ones would be slave states and which would be free states. Neither the industrial northern states nor the agrarian southern states wished for the other to gain more political leverage in Congress. When it became evident that the free states would have an advantage, the slave states seceded. They created their own flag, printed their own money, and elected their own president.
Abraham Lincoln, having been elected to his second term, understood that a United States of America that was divided would not survive outside aggression and endeavored to mend the rift. This became impossible when Confederate soldiers fired canons on Union soldiers at Fort Sumner, SC in 1861. In late 1862, President Lincoln issued a half-page mandate clearly stating that if the slave states did not return to the Union by January 1, 1863, then he would liberate their slaves. Since he was only addressing the parts of the states that were actively rebelling against the Union, slaves in areas not participating in the rebellion were not freed.
The Emancipation Proclamation was a political and military tactic implemented by Lincoln to hurt the Confederacy and end civil war, not to enact something as noble as freeing slaves as an act of humanitarianism. It was not meant to improve the lives of enslaved Africans; it actually protected slaveholders outside the Confederacy. Lincoln is known as the Great Emancipator, but his were not the actions of a benevolent leader or a benign country.
If the Confederate flag is flown in or around any government building or institution, then there is a problem. Some people believe it is their right as it reflects their heritage; others believe it is offensive as it symbolizes acceptance and encouragement of slavery in North America. Both are subjective attitudes that embrace and reject the symbol from a moot point of view.
The problem with waving such a symbol, especially in a government-affiliated facility is that it represents aggression against the United States of America. Currently such actions would be considered, at best, a separatist movement to be squashed by federal law enforcement. At worst it would be considered an act of terrorism.