I'm finding that this and other streaming services do this with .mkv videos. They are squished. VLC player can stream now but it is a bit glitchy. I hope Videostream can fix the aspect ratio glitch with mkv files soon.
Eh, I tried several times over the course of two days before giving up and posting here. Didn't get any helpful response from Videostream. I let the problem sit for about a week.
Didn't make any changes to the install or my system. Just decided to randomly pull up Videostream again yesterday as the standard user and... it works. Weirdness. Oh well.