you need to watch the movie again, that's not true. the rock was on a path to earth way before the government knew about it, and couldn't be warned because the rock hit a fucking spaceship's communications antenna (i will never understand why advanced humanity never makes ships capable of moving in fucking 3D). the bugs send an actual second meteor, but this time humanity has already set up defenses for this sort of attack. the bugs DO have space travel in the movies, that's how they colonized other worlds. klendathu isn't their homeworld. klendathu is their homeworld in the movie, but it's revealed after the first assault that they've colonized the entire system. it was also the humans who started the war. the mormons knew the world was inhabited (in the movie, this is shown in a blink and you'll miss it newspaper, because verhoven loves diegetic storytelling.) and still put down roots. they were slaughtered, which the government used as anti-bug unity propaganda, and then the bugs actually attacked earth. you can tell it wasn't a false flag because they intercept and destroy the second meteor with a newly constructed (but not ever claimed to be new TECH) moon defense system, which was where they detected the previous rock, even in the movie.
they used plasma launchers like they do to hit the ships in orbit, in the asteroid belt of klendathu.
he's a thin man from XCom. They've just figured out how to fix the eyes.