Was the Dieppe raid a military disaster?

I think from a purely operational standpoint, it can be said that it was a disaster. There were many signals leading up to the battle that indicated all was not well. The first rehearsal was a disaster and the increasingly bad weather, change of plans, and poor communication all worked to the operation's detriment. In any large engagement involving thousands of personnel, there will always be something that goes wrong. If merely one or even two things go awry (which almost always occurs), a plan can still be carried through to success. But when so many things break down at the same time, it is almost a sure bet that things will fail.
With that said, why did they go through with the raid? The British and Canadian commanders knew all of this but still pushed ahead. Why didn't someone call a halt? These are not easy answers simply because when you are talking about such a large-scale operation—an amphibious landing with troops parachuting in supported by multiple elements—you can't just say 'stop' and 'go' very easily. Think about all of the things that must take place: from ships getting in position, to airborne troops getting over their targets, to artillery support commencing at the right time (and doing so without the enemy finding out). You can see that once things get rolling, they are really hard to stop.
One could argue, as chief of combined operations Mountbatten did, that Dieppe served as a lesson for future operations, namely D-Day in 1944. It is true that much was learned after Dieppe, but something is always learned after a military operation whether successful or unsuccessful. All in all, despite everything learned from Dieppe, it is safe to conclude that it was a disaster.
http://www.bbc.co.uk/history/worldwars/wwtwo/dieppe_raid_01.shtml