Bad Blood (Pressure)

I attended one of the most aggravating critiques of my life today. I won't go into the details, but suffice to say that I called out a classmate on a piece that was supposedly about family and blood connections but her forms (spiky balls) looked obviously like viruses. Everyone then got very testy. I got a lot of flack for saying that, and the rest of the class came to the artist's defense saying that they they didn't see that, because they weren't familiar with what viruses actually look like. Even the former biology major didn't know what viruses look like.

I googled "virus" and this was the first image that popped up:
These are some images of blood cells that I found:



That white thing is a white blood cell.

Sometimes the extent of scientific illiteracy in this country (world?) takes me by surprise and slaps me in the face. And sometimes other artist's inability to take criticism gracefully takes me by surprise and slaps me in the face. It makes me sick to my stomach. The whole experience made me sick to my stomach and made me so angry my insides were quivering. The critique when downhill from there.

How do you handle people who get angry and defensive when you try to give honest constructive criticism? Where's the line between a piece being too literal and just not getting the point across at all? How much do you consider what each viewer brings to the piece and when, if ever, do you begin to disregard it? At what point is blood pressure medication needed?