A couple of corrections and clarifications of SheThing's writeup:
"Zack was said to have recorded his lyrics up to a year after the music was set."
Eight or nine months is closer to the truth. However, the way RATM used to write material was this: Music first, lyrics and vocals afterwards. So those nine months weren't spent entirely idle.
Nine months is one heck of a long time to pen lyrics for twelve songs, but considering the quality of the stuff Zack produced during this time, I feel it was worth the wait.
"Other band members ... were angered that he refused to show up for a RageTV special that MTV aired, leaving Tom and those other guys to chat it up with Carson Daly in an audience full of boy band lovers."
This, on the other hand, is not true. Rage played two songs, and in between Tom showing off his guitar and MTV playing videos, Carson Daly interviewed Zack about the Mexican students union who were protesting the recent rise in tuition from roughly 2 cents to $150, and aired a small documentary narrative that Zack had created, discussing the situation in further detail (This would eventually be released on the band's DVD, Battle of Mexico City, along with similar narratives on the EZLN and the WTO). I saw the show myself.
"Tour plans with Beastie Boys were delayed and then canceled completely."
True, but this was not the fault of neither Rage Against The Machine or Zack de la Rocha. Beastie Boys' Mike D had an accident while riding his BMX and ended up with a broken arm, leaving him unable to tour. Rage was on their marks, ready and set to go on tour. It was Mike D's arm that fucked up this project.