Those rats ran themselves to death, will we humans? We share about 92% of the genes[0] (on the first google attempt), what changes does that giant 8% contain?
Just pick up people like me, and make us run and give us food.
I doubt we will object if it means there's a possibility that we might help ourselves.
Are they afraid they'll make it worse? Sure that's a possibility, but that's the price to pay. I'm willing to pay that price if it means people after me, who have this wire crossed in their brains will be served better healthcare in the future.
Some experiments might not work, but we've just discovered another way to _not_ make the lightbulb, but the good news is that the lightbulb _will_ be made if we try n times.
[0] https://blog.23andme.com/23andme-and-you/genetics-101/geneti...