I have a rather similar problem. It's a physical defect...every foramen of every vertebrae has one nerve root. I have two nerve roots in the foramen of L4, and one leans against the other, causing relentless pain.
They can't remove or destroy either one because there is no way to trace exactly what each one does. For example, which one controls my legs? If one is destroyed, will I be a paraplegic? Would I be paralyzed on one side?
This might be type of the risk your doc is worried about....nerve damage beyond your spine.
This twinned nerve root was discovered during a major spinal surgery I had in 2016, when I was 61. I survived the surgery just fine, and I'm a pack-a-day smoker (I did not tell my surgeon). The surgery was to straighten a fairly severe spinal curvature. The surgeon implanted titanium rods and anchors.
That was pretty great until a year ago, when my spine began collapsing at the points above and below the rods. Your doc might be worried about a similar type of risk.
I totally sympathize, 911, and I've discovered over the years that spine specialists have a lot to learn. I encourage you to do some research. Like, my award-winning (literally) spinal surgeon told me he'd never ever heard of a twinned nerve root before. I did a little online research when I got home and found out it is rare, but other people do have it. There were even images.