I did not think 4 days of crying is ok, but I thought surely they are exaggerating! Age 11 seemed pretty right-on to me, too, not at all too young. 9 or 8, that seems a bit young.
My son doesn't seem distressed in the least when he considers the week away, so I think he is pretty ready.
Our boy scout troop emphasizes boy-led scouting, they didn't really much encourage us to attend, and frankly I'm not sure how either of us would attend for more than a couple days anyhow.
Ds11 seems stoked to go, and does have one friend he knows from boy scouts who will attend as well.
As for the fear about sexual abuse or other abuse/harassment from adults or older boys, I definitely feel that fear, however I think that ds has been well trained on what to do if anything like this comes up.
They do have a variety of rules to keep even the appearance of impropriety between an adult and any child from occurring.
He is very level-headed, I don't know, maybe I'm crazy but I don't want him to be too sheltered either.