As I recall, two Morton Thiokol engineers were arguing against a launch as it was too cold outside.
You don't quite recall correctly.
Not one single Morton Thiokol engineer would approve the launch.
Read that line again.
The company could not find an engineer, any engineer, to approve the launch.
A non-technical manager signed off on it.
“As I recall, two Morton Thiokol engineers were arguing against a launch as it was too cold outside.”
that’s one of the things i remember too ... they knew the giant casing junction O-rings wouldn’t perform properly in those temperature conditions, would fail, and the combustion in the solid rocket casings would not be contained at the casing junctions sealed by those O-rings,but instead would burn through the casings ...
Exactly right. I watched it live on TV and the memory still chills me. I recall that in follow-up reporting it became clear the launch decision was made mainly for PR reasons even though the risk was known. NASA didn't want any more delays because they might affect the Shuttle appropriations from Congress. Very bad decision!