Let's do a thought experiment asking whether Americans are for or against slavery. You might say, "What are you talking about, Williams? We fought a war that cost over 600,000 lives to end slavery!" To get started, we might find a description that captures the essence of slavery. A good working description is: slavery is a set of circumstances whereby one person is forcibly used to serve the purposes of another person and has no legal claim to the fruits of his labor.
The average American worker toils from January 1st to the end of April, and has no legal claim to the fruits of his labor for that period. Federal, state and local governments, through the tax code, take what he produces. A small portion of the fruits of his labor is used to provide for the constitutional functions of government. Most of what's taken, up to two-thirds, is given to some other American in the forms of farm and business subsidies, Social Security, Medicare, welfare and hundreds of other government handout programs. As in slavery, one person is being forcibly used to serve the purposes of another person.
You might ask, "Williams, aren't you a bit off base? Slavery means that you are owned by another person." Who owns a person is not nearly important as who has the rights to use that person. In other words, a plantation owner having the power to force a black to work for him would have been just as well off, and possibly better off, not owning him. Not owning him means not having to bear medical expenses and loss of wealth if the slave died. During World War II, Nazis didn't own Jews, but they had the power to force them to labor for them. Not owning Jews meant that working and starving them to death had little cost to the Nazis. The fact that American slaves were owned, with prices sometimes ranging from $800 to $1,300, meant that owners had a financial stake in the slave's well-being and they were not worked and starved to death.
You might argue that my analogy is irrelevant because unlike American slaves and Nazi concentration camp inmates, we can come and go as we please, live where we want, buy a car, clothes and other things with the money left over after the government gets four months' worth of our earnings. But, does that make much of a difference?