When you think about words and what they mean there is the definition of a word, but there is also the connotation of a word. So you can talk about what the strict definition of a word is, or what do people actually mean when they say it. The reason I wanted to talk about this is, I think a lot of anarchist misuse the word. If you want people to take you seriously you can't just change the meaning of words to make them mean what you want. Why do you think nobody really takes SJW's seriously? It's because they make up their own definition of racism to fit whatever they want to criticize.
So what does slavery mean? In the definition sense it means that people can be legally owned as property. I don't think to many people would try and make this claim. The government does tell you what you can and can't do, which is bad, but it doesn't mean you can be bought and sold like cattle. It is demeaning that the government can say "No! you are not allowed to own a plant. We know what is best for you." Just because the government treats us like children does not mean that we are slaves.
Now on to where most Anarchists try and really make the argument, what does it really mean when you say the word slavery. From a practical standpoint it means that someone can force you to work without paying you. There are two parts to this statement that I want to look at and the first is forcing some one to work. There are no laws saying that you have to work. If you have enough money you can sit at home and do nothing, if you have someone that is willing to pay your way you can sponge off of them, you can con other people out of money, or you can steal from people. While all but the first of these is immoral the actual act of not having having a job is not illegal, which means you are not a slave to the government.
Now I know a lot of Anarchists want to talk about the second part of my earlier statement, the part about not paying someone. So to start out I think taxation is theft. It is immoral, and the government wrong for doing it. The government is sealing our money by collecting taxes. However, is a thief a slave owner? Even if someone comes into my house and steals on a regular basis does that make them the master and me the slave? No, it doesn't. It means the thief is immoral and I am fool if I don't try and prevent it from continuing, but the relationship I outlined is just not a description of slavery.
So, the relationship between citizen and government doesn't meet the technical definition of slavery. It doesn't even meet a common usage definition of slavery. Look I understand what other Anarchists mean when they say we are slaves, and if you are trying to use the term as metaphor I don't have a problem with that. It makes me cringe though when I hear Anarchists actually try and defend the argument. They always end up going all SJW and trying to redefine a word to win an argument, and I really think that is a path you don't want to go down.