That's correct, at least in part. A few were armed, but only with sidearms and only with two rounds each - hardly the stuff to repel a suicidal attack. Both crew served weapons, forward and aft were unmanned as well. Lastly, even if they had been armed appropriately, the rules of engagement were such that it prohibited the sailors from firing preemptively.
While the official investigation cleared the ship's captain - he set force protection using the directed guidelines - the report clearly identified that those same force protection guidelines were woefully inadequate.
There are plenty of people for many years that have vocally stated that US service men and women should never stand watch with unloaded weapons, except of course in training, like boot-camps. But, common sense and practical responsibility continues to give way to political correctness. Command is more afraid of accidental discharge or lost weapons with ammunition than they are of actually protecting the principle - the principle in this case actually being US service men and women.
I think a lot of people tend to be under the assumption that the military has enough training to carry loaded weaponry around safely all the time. This is not the case. Go to any place there are guns (shooting range, firing line, gun show, gun shop) and you will see that safety is the number one priority. Not necessarily safety from other people and/or shootings like this, but safety from accidental discharge. When you are away from the firing line, mags are out, chambers are cleared and safeties are on. It’s no different here, really. I don’t believe that it’s 100% of a PC decision... even though that may be a part of it. It’s more for a stop-gap against accidents than anything else.
We may not see mags loaded in the guns, but that doesn’t mean they are defenseless. These guys are trained to load a gun and shoot in a matter of seconds.