A 10 kt tailwind by itself is not a problem
1000m by itself is not a problem
But these were associated with a very active Thunderstorm overhead the field and dumping rain, lightening and wind shifts all over the shop.
What does it take for guys to open up their eyes?
We are not paid to take risks, leave that to NASA and Test Pilots
Did they configure their aircraft for "if windshear conditions are expected"
I'll bet they used a derate to save the company money!!