Supposedly all the audio and video on Archive.org is in the public domain, does this mean that I could legally download a video clip off of their site and resell it for a profit?
No you can't. Read the TOS. "Patrons may download from the LMA with the understanding that the artists still hold their copyrights. All material is strictly noncommercial, both for access here and for any further distribution."
"Access to the Archive’s Collections is provided at no cost to you and is granted for scholarship and research purposes only." Nope!
Apparently it's not all, but there is a large portion of public domain content. There are over 24,000 public domain videos: http://www.archive.org/search.php?query=/metadata/licenseurl:http*publicdomain* AND mediatype:movies
Some of the content they archive happens to be in the public domain, but that in no way means that anything or everything they archive is. Nothing becomes part of the public domain just because it is on archive.org. All of those "movies" you cite are merely videos of government hearings, which by law, are in the public domain no matter what site you find them on.
The 24k I linked to were the ones marked as public domain out of more than 228,000 videos. There is a variety of different videos labeled as public domain, but yeah there are many government meeting type ones too
Yeah, I wasn't being literal, although I checked a lot and did not find much else. Anyway, I am sure there is public domain content, video and audio and I am sure images as well. The only point I was really trying to make is that you can't assume that just because it is on archive.org that anything is in the public domain.