Just to be clear, donations help getting into a specific institution to study. Which does give a leg up to get a position later (most often in a different institution), but that’s a second-order effect. It does not directly help getting hired.
What has this got to do with the topic of donations? Here the reason is completely different. Also, some university having a policy against it does not prove that it’s a widespread problem, it’s merely an indication that some problems happened that were high profile enough to make the institution react.
