That's kind of messed up. Except for the few that had been born or picked up along the way, everyone on the ship had only been gone from the general vicinity of Earth for seven years. Sure, a lot had happened in that time, but nothing that would blow anyone's mind.
The casualties of the Dominion War caused Sisko to violate his ethics(re: the deception that dragged the Romulans into the war). You don't think coming home after 7 years and finding that half of your graduating class had been killed(along with icons, idols, personal heroes and, for those whose families lived on attacked worlds, family members) would affect them? PTSD would probably be common-place. With the scale of destruction caused by the war, I should think they would need time to take it all in.