What’s up with these people they should be honored.
Some people have complex lives.
In General If the offered position is accepted, but later they withdraw it’s because they won’t pass certain core standards that are deemed necessary. They are told they won’t be selected and are asked to withdraw their nomination. Most are glad to do so.
They are. Because they are successful, many don’t want to give up a lifetime of work to do a job for 3-4 years.