Except there is no tradition of treating robots like slaves because their would be a new creation, and slavery is no longer tolerated since late 1800s. Heck, people started cracking down on it much earlier than 1860s, it's just slaveowners in America were particularly entrenchened because they thought ban on slavery would violate state rights.
There's also no tradition of treating robots as people. Robots would be seen as machines, and machines are treated as "slaves" currently. So, it would be pretty natural for people to continue that treatment, especially since sentience is not easy to determine.
Civil War was not about slavery, it was about rights of individual states vs federal government. Some slave states actually joined the Union.
Well, it depends which side you listen to. On a fundamental level, yes, you're right, the South was fighting for the right to secede. But, at the same time, the Southern US at the time was not in any way "democratic", since a large chunk of the population did not have the vote, and nor was it free. So, in that respect, the North had a valid reason to fight, and I think that the slavery aspect was quite important in the reasoning of supporters of the North (since it's a much more persuasive argument than "we want to be able to control the Southern states" is...).