<i>But, the imperialists have space weapons and the natives do not. Plus, the imperialists only want inert matter that exists underground. And, they are so evil they have no respect for life in any form.</i><p>An interesting interpretation, but not one born out by the film.  Remember this is a private corporation, so they likely have laws back on Earth they must answer to and it is likely that would ban such an overt destruction.<p>A "forced relocation" (and remember that for whatever reason they did try to drive them out with minimal loss of life at first) could likely be justified under their laws, and probably so can preemptively wiping out a massing army that could overwhelm their security with shear numbers.  Kinetic bombardment to wipe out huge swaths of the population probably crosses the line.<p>Also, it would not be surprising if they did not actually have space based weapons.  They had to jury-rig a transport to act as a bomber.  Its quite possible that either the company does not have them at all or that they have to travel all the way to earth and back (a many year journey) to get them.  And of course, that still only makes sense if their laws would let them use those space based weapons.