"But what if you need Microsoft Office, and LibreOffice can't suit your
needs? "
You're mixing up things. Offering choices is not the same as using the whip,
i.e. actively holding somebody back.
You describe a slave owner, telling his slave:
"you are free to go, but then I won't give you food anymore."
I don't think we can actually talk about slavery anymore, even though the
"slave" will have a hard time getting his food elsewhere.
If you disagree, almost every job in an economically bad environment would be
considered to be slavery then.
Do you see where I'm coming from?