With respect, you don't use 238U because:
1) It is much more expensive than lead.
2) It is much harder than lead.
3) It is much more radioactive than lead.
4) It is much more difficult to obtain than lead.
5) It is pyrophoric. Lead is not.
Half of those things on your list pertain to the environmental impact of using DU in projectiles. But the liability tail of doing so is so great that only a government that could immunize itself from the economic consequences raises the cost of using DU by a civilian to a level outside of anything affordable. Besides, don’t you know satire when you read it?