While that may be true, the groups that make these decisions are the same folks who decided F-4s didn't need guns, because the day of the dogfight was over. If F-4s had been used under the conditions that these people envisioned, they would have been right. However, the rules of engagement during Vietnam precluded use of the F-4 as designed, so you had pilots get into some deep doo-doo because they didn't have a means to retaliate against enemy fighers after launching all of their missiles. I can easily think of at least one reason to have at least limited armor (which i have no idea if this vessel has or not:) to prevent an attack similar to what happened to USS Cole. You certainly aren't going to protect yourself from a speedboat bomb, while in dock, with a phalanx.