Given the choice I'd kill literally every monkey and pig on the planet if it meant we had the technology to cure paralysis.
I honestly can't comprehend the alternative. You'd walk up to some poor sap paralyzed from the neck down and say "Gee I'd really love for you to walk again but I'm a little bit more concerned about the pigs and monkeys?".
I think what you're failing to comprehend is that some people have a trait called empathy which prevents them from genociding the better part of a billion individuals for the sake of a few being able to stretch their legs.
We kill 80 billion animals for food every year. Pretty sure 1500 to advance science is nothing in comparison.
And I wish we had a better way, but we just don't yet. Bioinformatics is working on creating virtual bodies, but we're not there yet, it's decades away.
I honestly can't comprehend the alternative. You'd walk up to some poor sap paralyzed from the neck down and say "Gee I'd really love for you to walk again but I'm a little bit more concerned about the pigs and monkeys?".