I wonder what you guys thought animal testing is about, if this is somehow surprising to you. This is just another day at the office for the people running these experiments. The issue is not "Elon doing animal testing" but animal testing in itself.
However - if you think we shouldn't do it then you should also be aware of the tradeoffs. Without this cruelty there's no modern medicine either. Also, if you complain about this but eat meat then you're a hypocrite.
It's easy to say as someone with a healthy brain. A blind, deaf or a paralyzed person might feel different once there truly is a way to get your sight back with this technology.