The text before your quote is "since we cannot import haggis to the US our haggis for the US market is made in Bangor Maine" and the text immediately after is "all haggis made in the US except our haggis links is in an artificial casing".
In other words, you pointed to a source which confirms that it is possible to make and sell haggis domestically in the US.
That's like saying hamburgers are allowed, you just can't have any ground beef in them. Haggis is made from sheep's lung - that's what it is. They just do a phony version for the Americans and call it haggis anyway.
The Wikipedia page also references a 1615 recipe for haggis which does not require sheep lungs, saying "oat-meale mixed with blood, and the Liver of either Sheepe, Calfe or Swine, maketh that pudding which is called the Haggas or Haggus".
To me this sounds like the old gatekeeper question of who gets to assign authenticity. Since things called "haggis" are sold in Scotland (or at least the UK), and do not have sheep lungs, I think that means it is incorrect to say that just because a product sold in the US or Canada does not have sheep lungs in it, it cannot be called haggis.
I don't know if you're an expert in Haggis, so maybe you know more than me, but this FAQ says otherwise.
http://www.scottishhaggis.com/index.php/frequently-asked-que...
> the USDA does not allow sheep lungs to be used in manufacture