Is it fair to say a gradient exists in my mind but I don't have it quantified?
There are nationals from countries where I wouldn't have any concerns whatsoever, even if they wanted to buy something scary like a nuclear power plant; England, Canada, France, Nigeria, South Korea, Japan as examples. On the other end of the spectrum there are nationals from countries that I believe concern is warranted; China, Russia, Saudi Arabia, Afghanistan, Iran, etc.
The business owners and directors should have autonomy to do what they please with their business, though. Perhaps the balance point is this, businesses can be sold to anyone from any country but the purchasers have to be vetted AND the US government can force the sale from the new owners if those new owners pose a credible risk to national security.