Your link does not support what you are saying. The linked article says that: (i) there aren't enough studies for the toxicity of depleted uranium (ii) we know that uranium is chemically somewhat similar to lead (iii) there are a lot of studies about the toxicity of lead, so (iv) because of (i)-(iii) for the time being it and for modelling purposes it may be useful to assume that depleted uranium has similar toxic effects to lead.
In other words, the article admits that the author does not really know about the toxicity effects of DE and uses lead only as a best guess.
Furthermore, the article clearly distinguishes between the toxic effects and radioactive effects. Depleted uranium is less radioactive than the usual uranium, but it is still plenty radioactive. And the effects of radioactivity are pretty bad when you are breathing the stuff in.
when you say "lead bullets" do you mean gun bullets, or armor piercing bullets / projectiles? a normal bullet does not vaporize and contaminate the whole area in the same way vaporizing projectiles do...
Depleted Uranium is not designed to vaporize. It has a boiling point (3818°C) more than twice that of lead (1740°C). It's atomic mass of 238 is considerably higher than Lead's 207.5. It packs quite the punch when put into a slug, but does not reach temperatures where it could vaporize. Certainly particulate matter would be ejected from the impact, though as with most slugs.
That said, what was done here is despicable and it is clear evidence of a war crime.
The DU projectiles are intended to fragment in ways that lead does not, as on impact parts of the projectile shear away and it "self-sharpens" when penetrating.
The energy involved is also more than sufficient to hit that temperature. When a high-velocity shell impacts something it will deform and convert a lot of the kinetic energy to thermal.
The whole thing doesn't melt, but parts of it do, and the vehicle it hits gets absolutely thrashed.
These things cut through pretty much any armor like it's not even there. During the Iraq war they'd even hit tanks by firing through the tops of sand dunes, aiming using thermal imaging.
when an uranium projectile hits the armor, some of the uranium burns into uranium oxide, a dust of which gets dispersed all around. Big problem in Serbia too - in 1999 NATO used 30K+ units of uranium ammunition there.
I suppose whatever metal is used in a cumulative charge, a significant amount of it gets dispersed far and wide while a jet of the molten metal is piercing several inches of armor.
Copper, lead, whatever else, should contaminate all around as fine dust.
In other words, the article admits that the author does not really know about the toxicity effects of DE and uses lead only as a best guess.
Furthermore, the article clearly distinguishes between the toxic effects and radioactive effects. Depleted uranium is less radioactive than the usual uranium, but it is still plenty radioactive. And the effects of radioactivity are pretty bad when you are breathing the stuff in.