I have spent about 3 whole days searching for a Google Earth API extension that would enable users to perform selections of placemarks by either clicking multiple points, OR by drawing a polygon. I didn't budget or spec this functionality because I was confident that this is the type of thing that would be readily available for Google Earth. Turns out I was wrong.
At any rate, I am not asking anyone to write the code, I am hoping someone has come across a javascript library that enables this functionality.
As you have discovered GE plugin does not support drawing or dragging without writing some code yourself.
There is an extension library that I have found useful for draggable placemarks. Use makeDraggable().
Example here: http://earth-api-utility-library.googlecode.com/svn/trunk/extensions/examples/draggable.html
Source here: https://code.google.com/p/earth-api-utility-library/source/browse/trunk/extensions/src/edit/dragging.js