In short, yes, at the time I think it was. Slavery wasn't how it is now. It wasn't looked at as a heinous act in that time period. In fact, it was as common as say, owning a hair dryer. I think that's a good analogy, as harsh as it sounds. Slaves were thought of nothing more than property. How preposterous would it sound if the government told us we were no longer allowed to use hair dryers? As far as I see, there were three major reasons that slaves were acknowledged in the Constitution at all under the three-fifths act. One of the reasons is that slaves made up a large part of the population, especially in the south, during the time. Another is that it made the slave owners happy, which
was extremely important during the time. The third is that it was something the northerners could live with. Slaves made up a large part of the population percentage in the south. A higher percentage than the slave owners did due to the fact that a slave owning family would own enough for there to be a huge proportional difference. This made the population difference between the north and south large if you excluded the slaves as eligible voters. The south loved their slaves. Not literally loved the people themselves, they loved the business aspect of owning slaves. Most were willing to fight for their right to have slaves, not that this was an issue that was being publicly challenged yet. Having their slaves made them a lot of money, making most southerners extremely wealthy. This was important to the government. Although some may have thought slavery was wrong, it was more important at the time to keep the two sides united, especially since the south had money. Thus the three-fifths rule was instilled, which made every slave count as three-fifths of a person, therefore three-fifths of a person. Although the northerners weren't happy with the fact that the south was given extra power due to this law, it was one that could be lived with. This was the goal of writers of the Constitution at the time. They knew even then that the abolishment of slavery, or even the questioning of it, would result in a major feud between the north and south. Because of this, they gave the south more or less what they wanted while keeping the north content enough to not start a war... Yet.