> They are just unelected so they can do unpopular things without it impacting their careers.

Yes, this (to an extent), but more importantly, they're also experts. The people hired at these agencies aren't politicians, they're professionals.

Seems to me most congress people can barely tell their ass from a hole in the ground these days. Do we really need them chiming in on what medicine is okay and what isn't?

Do you think they are the ones writing the 1000-page bills they pass on a weekly basis? Laws are also generally written by experts.