No-one's ever truly and completely free, anyway. So why choose death to avoid compromising something you never really had in the first place?
Care to explain that contention? Unless you believe that being bound by reason, rationality, and natural laws compromises freedom... 
I'm sure she means that between parents, government, law enforcers, ect. One is never truly free. When you disobey to a certain extent, you will be punished. Either by being grounded, jailed, or restricted in some other way.
There's always someone or some people over you.
Yeah, basically that, but not only that. Anyone who has a job isn't truly free: you bind yourself to be there a certain number of hours and do what your boss or whatever tells you. Of course, it depends on your definition of what freedom is. However, if you take it to its full extreme, freedom would mean doing whatever you want as and when you want it: including murder if that's what you wanted. Consequently, I feel that not everybody could be completely free to do what they wanted all at the same time, because everyone i s different and thus conflicts, so one person's freedom would restrict another. Which is why we have government to try and impose some order on things. But in turn, that limits freedom.
I do agree that there's a huge difference between involuntary infestation, which is very limiting, and the restrictions on freedom that exist in most democracies. But there are still some restrictions. However, I would argue that VOLUNTARY infestation is no worse than having a job or entering into some other commitment: you give up a portion of your freedom in return for some kind of reward or something that's important to you, whether that's money or companionship or very advanced plastic surgery (Taylor) or the chance to help fight for Earth's freedom (Tidwell and the other PM hosts).
I guess what I'm trying to get at is that 'free' is a very abstract concept, and it means a different thing to everyone. Too abstract for me to wish to be dead if I didn't achieve it
Yeah but that doesn't mean you're not free. You're still free to do whatever you want just like society is free to punish you for it. Consequences don't restrict freedom.
(Sorry, free will was my favorite debate topic in philosophy - compatibilism rules!)
What about imprisonment? That restricts your freedom. Although consequences may not ACTUALLY restrict your freedom, they do ATTEMPT to. The Yeerks are just more efficient at restricting freedom than humans, who have to have punishments because they can't physically prevent undesirable acts so they have to have deterrents. And things like what you're taught to do as a child mean that you never even think completely freely, either. There's obviously a continuum between total freedom (a pretty abstract concept, there are always going to be some kind of restrictions, self-imposed, imposed by others or just a result of circumstances), and involuntary infestation which is as close to complete loss of freedom as you could possibly get (at least in the Animorphs universe, where Visser Three's potion to remove free will doesn't work). It depends how you personally define it.
