The holidays are part and parcel of the gross fraud, wrong, and inhumanity of slavery. They are professedly a custom established by the benevolence of the slaveholders; but I undertake to say, it is the result of selfishness, and one of the grossest frauds committed upon the down-trodden slave. They do not give the slaves this time because they would not like to have their work during its continuance, but because they know it would be unsafe to deprive them of it. This will be seen by the fact, that the slaveholders like to have their slaves spend those days just in such a manner as to make them as glad of their ending as of their beginning. Their object seems to be, to disgust their slaves with freedom, by plunging them into the lowest depths of dissipation. For instance, the slaveholders not only like to see the slave drink of his own accord, but will adopt various plans to make him drunk. One plan is, to make bets on their slaves, as to who can drink the most whisky without getting drunk; and in this way they succeed in getting whole multitudes to drink to excess. Thus, when the slave asks for virtuous freedom, the cunning slaveholder, knowing his ignorance, cheats him with a dose of vicious dissipation, artfully labeled with the name of liberty. The most of us used to drink it down, and the result was just what might be supposed; many of us were led to think that there was little to choose between liberty and slavery. We felt, and very properly too, that we had almost as well be slaves to man as to rum. So, when the holidays ended, we staggered up from the filth of our wallowing, took a long breath, and marched to the field,--feeling, upon the whole, rather glad to go, from what our master had deceived us into a belief was freedom, back to the arms of slavery. (10.17)
The slave masters gave their slaves a holiday at the end of the year as a way of appeasing them. By getting the slaves to spend their brief period of freedom drinking and acting like animals, they could trick the slaves into thinking their only options were to be a slave to alcohol or to human masters. Though he might be right about the masters' motivations, Douglass also sounds like he's picked up some religion from the abolitionist crowd he's running with: it was common in the mid-nineteenth century for really serious Christians to say that alcohol made drunkards into "slaves."