Ignorance, or just as an excuse. IMAP supports both direct SSL, and even better STARTTLS. Just about every IMAP server, including Exchange supports this easily.

I don't understand why people cling to POP3.. I consider it LESS secure than IMAP, not from a network security standpoint, but from the standpoint of "Oh god, my laptop crashed, all my mail is gone" point of view.

It took me years to convince my friend to switch from POP3 to IMAP. The thing that finally got him was having email in webmail and Eudora at the same time. Of course a year or so later, laptop crashed and he didn't have to worry about his mail. Finally got what I had been saying for a long time.