Several things, but to name one, none of those examples are actually representing “scientific consensus” (except for the margarine example, and medical science is notoriously tricky and subject to lots of noise and false signals).
Science didn’t even “exist” until the 1600s - well after the timeframes of nearly all of those examples. [0]
Your examples demonstrate “social consensus”, “religious consensus”, “proto-medical consensus”, but not “scientific consensus.”
[0]: a note that to say “science started at time X” is subjective, of course, but the modern formal framework of science is relatively new and putting it around the time of Isaac Newton’s Principia is probably a good rough guess.
I would not consider Galileo to be a representative of modern science, more of a precursor.
Whatever consensus you wish to call it, it was the consensus of those in power in society at the time that believed they knew the truth.
Galileo was a scientist whether scientist was a recognized term at the time or not. He made observations, and developed theories based on those observations. That's science.
George Washington's death was hastened by doctors who bled him, 200 years after 1600.
And how about Darwin's theories, Lysenkoism, Phrenology, etc.?
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