Most diseases are pathological changes, often with no cause. Are you saying autoimmune diseases are our own doing (Well, it is body vs body, but we don't choose to) or maybe (most types of) cancer? Yeah, there's a hell of a lot of lifestyle diseases - but humans are humans, they still need treating.
Yeah, that's quite true. Animal testing is the second stage in testing. They are testing on supercomputers first to test their viability and efficacy in humans. Then tested on animals to see if they're any safer.
As for animal testing - I'm for it. You're probably right in that fact we have no right to say who is the superior species - but at the end of the day, humans vs animals, I'll pick the animals to be tested on everytime. Until a fesible way of testing new drugs is found then there's no other often, in my opinion, and British Law says so too!
I challenge any animal right campaigner to refuse their treatment though. Every single drug/vaccine/intervention has been tested for safety on animals before hand. If its life vs death, I wonder who would have the balls to stick with their principles?