Perhaps people like you (and I) are not the target audience. I've always felt Dropbox was more of an "typical user" (as opposed to power user) file sync; I used it some years ago but never really liked it, I roll my own now.

I wonder whether Dropbox looked at some stats and realised that many of their users are on beginner-friendly distros/desktops and that such a requirement would help (them) more than it would hurt (users).