It allowed slavery and found Scott to be property.
13th amendment to the Constitution
Scott wasd denied his freedom. The Court interpreted the Constitution to mean that slavery was legal in every state of the Union, because it said a man's property was sacred, and slaves were property.
The Dred Scott decision stated that people of African decent imported to America were not citizens and not protected by the Constitution. The fourteenth and fifteenth amendments nullified that decision.
Because it said slavery was protected by the Constitution.
The Supreme Court decision in the Dred Scott case declared that slaves were not citizens, so they had no rights under the Constitution and no legal standing in court. It also ruled that Congress had no power to ban slavery in the territories, essentially allowing for the expansion of slavery into new regions.
It declared that slavery was legal in every state of the Union according to the Constitution.
The Supreme Court interpreted the Constitution as it was understood in 1776 - that a man's property was sacred, and slaves were property. This appeared to mean that no state could declare itself to be free soil.
The Court interpreted the Constitution, as they believed the Founding Fathers would have meant. A man's property was sacred. Slaves were property. Therefore slavery was legal in every state of the Union. It added that a black man could not be a citizen of the USA, and could not take a white man to court. So Dred Scott's owners had no case to answer.
It simply declared that slavery was legal in every state of the Union, because of how the Chief Justice interpreted the Constitution.
It appeared to mean that slavery was protected by the Constitution, and could not be banned from any state of the Union.
Applauded by the South, who thought its interpretation of the Constitution meant that there was no such thing as free soil.
The Supreme Court denied Scott his freedom on the grounds that slavery was protected by the Constitution. (They judged that the Founding Fathers would have included slaves in their definition of 'property' - which was declared sacred under the Constitution.) This decision infuriated the influential Abolitionists in the North, as much as it delighted the South, and deepened the division between the two sections.