I'm a scientist and I worked with lab animals during my studies. I can assure you they are treated in the most humane ways, with very rigid standards (at least in my country). They're even treated better than the poor people! Their importance for medical breakthroughs are crucial; we can either bitch about that and live in a medieval way dying by age 40, or accept their sacrifice while we embrace our modern way of life and live beyond 80. So let's not be hypocritical.