The point is that we do not do that when a loved one has a contagious disease. We've had too many pandemics in our past and we understand how disease is spread. My ancestors survived several pandemics that decimated the population of Europe, as well as the 1918 pandemic that is still a source of fear and horror.
Would you, personally, hug, hold, and kiss your loved one that you know is dying from a deadly contagious disease like Ebola? If the answer is no, then why would you assume that anyone else raised as an American, and steeped in American culture, would do that?
The point is that there are hundreds of thousands of low information people out there. When a loved one comes down with what looks like the flu do you seriously believe that nobody in the family is going to touch that person? That they're going to wear a hazmat suit whenever they're around them? They're not going to touch the soiled bedsheets and clothes? Seriously?
I have had relatives with suppressed immune systems.
You hold their hand. With a glove on. With a mask on.
You make sure that you do not bring any ‘bugs’, ‘germs’ into the room.
Its that in reverse.