The language is certainly intimidating
I certainly don't see it as a nefarious plot by the government and if it is a site for dealers and not the general public, as z says, it probably has some reason to carriy the warning. If the feds wanted to somehow suck in the general public for some reason I can't imagine it would do so in a much more surreptitious way.
As a public web site it is just an example of governmet bureaucracy unintentionally creating an opportunity for lite comedy/entertainment.
(The government is powerful, but in the end we are protected by our irrelevance)