Really, dropbox is probably more secure than most complainers' computers; but when you say things like

    - All transmission of file data occurs over an encrypted channel (SSL).
    - All files stored on Dropbox servers are encrypted (AES-256)

and this turns out to mean "file metadata may not be encrypted" and "all files stored on Dropbox servers are encrypted with the same key (AES-256)"... well, people are going to call "snake oil".