At the volumes and surface area we’re talking about, is it any more than a blip? Say one rocket explodes. What’s the worst result of that fallout? Is it worse than peeling a banana or flying in a jumbo jet?
It's not cost effective. (Same reason we don't encase it in giant synthetic diamonds or bury it in the earth's mantle)
Plus the material is valuable & space launches are dangerous. Launching to space probably introduces more contamination risk than any other option short of intentionally making dirty bombs out of it
Some fraction of rockets explodes during launch. Also dropping things into the sun costs a lot of energy because you have do decelerate it from earths orbital speed (30 km/s) or whatever you are trying to drop will just orbit around the sun.
