So what should they have said in the beginning? If they don't give technical reasons, they will be accused of talking down from their ivory tower, dictating policy with a 'just trust us' attitude, or of being biased/political.
But if they give technical reasons, people will nitpick those, especially if the data is incomplete or evolving.
There were lots of people being correct and nuanced, but they were drowned out (partly for political reasons I suspect).