They're not, and that's not the definition of Slavery. You're just trying to redefine something by using the wrong word and mistaking pedantry for real argument. Slavery where you get paid wages for your work, have a set retirement, and get a pension for your service is a hella weird definition of slavery.
Slavery is forced labor. It's a pretty simple definition. For wages, are sex slaves controlled by a pimp, who can't leave, but are given cash not slaves because of the cash? No. And the rest of the features similarly fail, as they do not hit makes slavery wrong. If the slaver only held his slaves for a limited time period, that does not make him somehow moral. The payment after the fact could be reparations for the wrong he did, but again, does not justify doing the wrong in the first place.
The key feature of slavery is being held in forced servitude to another who holds you in bondage. Again, what feature of slavery do you see that conscription does not meet? You cannot leave. You must work. This isn't pedantry, this is uncomfortable.
Fundamentally one of the issues that tends to twist your logic so badly is that property rights are positive rights. You try to reverse it to a negative right by saying it's "the right not to have your stuff taken" but that makes no sense without the positive right to own stuff in the first place. Because you're basing your entire stance on a positive right, your arguments against other positive rights fall flat.
That's not how positive rights work. At all. A positive right is one that requires action: the right to education, healthcare, social security, etc.
A negative right is one that requires inaction: the right to speech, property, bodily autonomy, etc.
The 'right to own stuff', even if we accept your weird phrasing, is still a negative right. It requires others to not do stuff.
For example, the Wikipedia page lists property rights as a negative right:
en.wikipedia.org
Now the right to "have the state enforce your property rights" (or other negative rights)? That's a positive 'right'. It's the reason we have a state, and clearly, it would require a cost to maintain it, so we violate negative rights a little (a little evil called taxes) in order to prevent more violations.
Nobody who considers property rights the foundation of their philosophy should ever object to the paying of debts owed.
Yeah. But debts are entered into consensually. What we described above (the taxes but more importantly the conscription)
is not a debt. It is an evil. I want as little of it as possible in people's lives, as each instance is an injustice. I still acknowledge it as necessary, I just want it to do evil less
because stopping evil is the entire point of government.
Also, your comparison of a family to a government is completely wrongheaded, again. Again, grounding for naughty words is fine in a family, but censorship is not. Forcing a kid to go to a church is fine for a family, not for government. And I could go on. These are not similar things.