Launching James Webb was part of the European part of helping with financing James Webb. And of course they picked their own rocket to do so. Ariane 5 was not

Launching James Webb was part of the European part of helping with financing James Webb. And of course they picked their own rocket to do so. Ariane 5 was not picked because its the most reliable. Ariane 5, Delta IV and Atlas 5 all had the necessary certification to launch James Webb. Falcon 9 and Falcon Heavy also have this level of certification, but of course they got it after James Webb was already assigned. Your comment is just a fundamental misunderstanding of how launch vehicle selection works and how NASA certification levels work. Please stop with these uninformed comments.