Standard practice on the FreeBSD mailing lists is to reply to both the list and the original sender. That's because:
the list is open to all -- it's pointed out as one of the first places to look for support in the standard Message of the Day (/etc/motd) which will be about the first thing you see when logging into a newly installed FreeBSD system. So many of the questioners may well not be subscribed to the list.
replies to questions should always be copied to the list, as they will then be archived in several places around the net (not least http://lists.freebsd.org/pipermail/freebsd-questions/) That collected knowledge is a very valuable resource which you should always search to make sure that your questions haven't been asked and answered before now.
The two messages you're seeing are the direct reply to you and (the one with the extra footer) the reply delivered via the list. There's several ways of avoiding having to plough through everything twice. First (and most obviously) you can alter your subscription settings via Mailman. Go to: http://lists.freebsd.org/mailman/listinfo/freebsd-questions
Then type in your subscription e-mail address in the last text box on that page and click the button beside it that says 'Unsubscribe or edit options'. On the next page, type in the password you used when you originally subscribed and click on 'Log in'. On the next page, scroll down until you see the 'Avoid duplicate copies of messages?' entry. Click 'Yes' on the radio button to the righ hand side, then click 'Submit My Changes'.