Germany has some rather asinine export restrictions regarding firearms meaning it's that much MORE expensive for HK to export to the US for civilian sales. HK does NOT maintain nor operate a domestic based plant meaning ALL of their civilian firearm products need to pass German export restrictions.
Due to these restrictions HK stands to make much more money off of purely military/LE contracts which do not need to pass the same export standards. This is the exact business plan that HK has adopted meaning out of their net revenue, only a small portion of that comes from the civilian market. It is much easier for them to win a contract for 1,000 MP7s than it is for them to import the same value of firearms to be sold in the civilian market.
Sure, they'll sell their products to civilians, but ONLY if it doesn't require them to get around any export restrictions to do it. The major downside is because HK doesn't have nearly the same volume of US based contracts for their small arms as does FN or Beretta, they are unwilling to invest in the money to build a domestic plant just to cash in on the American civilian market.
Edit: Also have no idea why someone in the industry wouldn't already know this or more. Then again looking at your website, you're very new to the industry in which case good luck with your success without knowing basic information regarding major industry players.