On the whole, I don't mind KA's sub-texts. I even agree with most of them, especially her ideas about how war changes people, how you can't defeat an enemy without beginning to become them, and how no group of people (or aliens) is ever 100% evil. They're good messages to spread, and they're probably true.
There were a few of her messages, however, that I would disagree with.
The near-complete absence of guns from the series (I mean, the number of times the Animorphs have fired a weapon can be counted on the fingers of one hand) was something that, when you stop to think about it for too long, reeks of
fridge logic. Yeah, she was trying to send a message. Guns are bad. But still, it wasn't done in a way that made a whole lot of sense. Most people would have been pretty keen on stealing weapons in the Anis position. She could have found a better way around that one.
The other message I didn't like were all the moral values that Cassie upheld. I don't dislike Cassie as a person. She's a lot like me, actually. And I agreed with her morals, for the most part. But it became so obvious, later on in the series, that she was just being used as a vehicle for K.A.'s own point of view. I mean, come on, she was
never freaking
wrong. She was just there to prove to the reader that morality is good, and life is sacred, and if you hold on tight enough to your morals you can survive anything.
Which is a message that I don't agree with in the first place. If you hold too tight to your morals, they break. If you try too hard not to change, you will snap and then change anyway.
But, as Terenia said, you can't ever write an unbiased story. You have to write from your own personal experience and write what you know, or else your story will come across as fake and boring. So, on that level, I'm glad that K.A. wrote from her heart, no matter what her thoughts about these things might be. Animorphs would have been a very different story if she hadn't.