Your first instinct is correct. That is pure, unabashed bullshit. For decades prior to the ACW there had been an established network for runaways to escape their shackles. During the ACW itself camps were established in territory held by federal troops in order to give the thousands of fleeing freedmen some place to go. Arlington National Cemetery was one such freedman's camp during the war. To say that any former slave was unhappy about their emancipation is plain racism and revisionism of the worst kind.

Perhaps some freedmen were unhappy following emancipation but it wasn't due to being emancipated. Unfortunately after the war there was little done to support freedmen. Many had to continue working for their former masters as share croppers and few escaped poverty. The Black Belt in modern Alabama is a holdover of poverty stricken descendants of former slaves. Even in the rare circumstances when blacks began to achieve some financial independence and wealth they were targets of Lynching and riots (here is a list of lynchings by year). The white population of the south did everything in its power to continue the subservience of Black Americans and to regain the power dynamic that they had lost. They even went so far as to form and support a terrorist organization bent on killing and intimidating blacks and the agents of the federal government.

I'm gonna go outside the bounds of askhistorians here but...this is the sort of thing that cannot be allowed to stand. You have an obligation as a citizen and a student of history to combat blatant ignorance and racism of this statement. This is demeaning, infantilizing, and disrespectful to everything African Americans have endured and accomplished in American history. It follows in the same line as neo-confederate apologia and racism has for over a century. It seeks to remove agency from Black Americans and to minimize the wrongs of those who chose to systematically disenfranchise an entire race.