You won't get an answer because there isn't one, IMO. If the professor isn't interrupted by the sneeze itself, how are a couple of "bless you"s soooooooo much more disruptive? And if he/she IS interrupted by the sneeze, are a couple of "bless yous" just THAT much more disruptive? Or is the professor on a power trip that makes him/her think it's ok to grade students negatively for being polite? That's a rhetorical question, I don't expect an answer.
And I have been in classrooms more stressful than you'd think. Just because a person's opinion differs does not mean that person lacks the life experience you have. JMHO.
The difference is that we all assume the sneeze was involuntary, so nobody's going to fault a student for that.
The chorus of "Bless yous" is entirely voluntary and a willful interruption of someone who is speaking (whether the speaker is I or another student). And why is it necessary? (You keep saying "a couple of bless yous" when I have told you time and again that a chorus of bless yous often erupts and takes several minutes to subside.)
You are right: i was wrong to make assumptions about your educational background, and for that I apologize.
But put your self in my place for a moment: I used to have 2 hours (minus a break) to explain Sophocles' OEDIPUS and Aristotle's POETICS to 17 and 18-year-olds. And I had to explain the play as a dramatic work, not the "lesson on fate" students are taught in high school.
To do the above, I had to walk students through both works, step by step, explaining Greek beliefs, problems with translation into English, etc. and so forth. And I had to do so with enough humor to hold the attention of teenagers, while also allowing them to ask questions so they didn't get lost.
An interrupting chorus of "Bless yous" required me to back up, find a suitable place to start over and think of something entertaining to recapture the attention of the class.
And still I ask: why is saying "bless you" so important? Why does acknowledging a sneeze justify interrupting someone who is speaking, someone who has spent hours organizing the material so it will make sense to teenagers and now must re-organize the material to account for the interruption?