"Not quite true"
But why assessing risk in the wrong way? To save money. Performing complex, exhaustive tests cost money. Keeping the required skills on board costs money. Delaying a launch costs money.
The "cold" launch was outside the required parameters - the fact they assessed "it could work anyway, as far as we know" was due to costs reasons - and when you look for a justification, you usually find one.
The risk of detaching stuff at launch should have been examined extensively - they instead relied on luck. "If the pieces are small enough and don't hit a sensitive part, we're OK..."
"Had the analysis been done correctly,"
And why it wasn't? Because of costs and delays? Then, they had to pay the price of two catastrophic failures, and fourteen lives lost.