I think there was something more to this show than just mermaids. I didn't see more than the first 30 minutes, but at the beginning one of the scientists says that he didn't believe in the 9/11, JFK, and some other conspiracy but then he supposedly saw the mermaid and his world view was shaken or something. So, maybe this program was a subtle way of getting people to put stock in other conspiracies by making it look like there are actual mermaids. I mean, maybe there are mermaids, but regardless, I think the show also had the purpose of getting people to think more openly about "conspiracy" theories. So, that would be a more likely motivation for the page being removed.

Although, I went to the animal planet site and it's still up. Are you sure this other site was officially linked to the show?