Without seeing the actual project and only getting one side of the story it is really impossible to say if the school was harsh or not. Teachers don't give out zeros lightly, especially to honor roll students. There has to be more to this story.
BTW, our kids learned citation in 4th grade when they started writing research papers. Copying a work word for word and putting quotes around it is still a pretty lazy way to do a project and I would probably not given credit for that either. The whole point is to be able to read something and put it into your own words and THEN cite the works. With computers today it is simple to cut and past off a story, cite your works and in 5 minutes have a 4 page paper done. Not exactly what teachers are after wouldn't you say?
Also, you only have 2 A students in your school? That is odd.
Some little fun facts about the only K-12 school in a National Park. We have approximately 300 students. That includes 'illegals', students who live in the park with family for the school year who are from the reservation (there are many Native American reservations around here), and students who are bused from 26 miles away. Our school is held to every state standard. We are financially strapped as we don't have the residential or business tax revenue most schools have (There are no private residences in the park and the nearest town has only 3. Xanterra, the business that operates in our park, does not pay any taxes to the school). We have a staff of approx. 60. We also have a high turn over rate. Most park service and Xanterra employees stay less than 3 years. We are considered oldtimers at 9 years.
There are 24 students in the 6th grade class. About the same in the 7th grade and closer to 40 in the 8th grade. Only two of them are A-Honor Roll students, both of them are in the 6th grade. Our son received awards in Art, Math, and Spanish. Feel free to check the Williams-Grand Canyon Newspaper which listed all the honor roll students.
However, the point of mentioning that he is a straight A student was not to say that he HAD to have straight As. It was to demonstrate that he is a smart student who has done well on homework, classwork, and tests. Which is why we think this happening is so out of place.
The students were not asked to write lengthy reports. We're only talking about the information that goes on the Project board.
The students have definitely NOT covered citing, etc in their Language Arts class and have not written any research papers in that class. Most of their work to this point has been creative writing.
The teacher does use a rubric when grading which she previously told us was difficult to understand and didn't want to explain it to us. I am a trained nuclear engineer - I think I might have been able to understand it.
The math teacher for middle school told our son that, "Miss Smith does things her own way."
The art teacher was surprised we weren't called in before our child was told he had a zero.
I was surprised when I went to the principal and he told me that plagiarism was cheating and he deserved a zero but to his knowledge this was the first time the school had done this to someone in the 6th grade.
Another teacher said that routinely she had to have science fair projects that had uncited sources fixed before they were judged and it was standard procedure to get with the student and show what was wrong and fix it.
We appreciate the suggestions and will be talking to our son more, both about what he is comfortable with and what happened in the class room.
Again, we are not asking for full credit. We would like to see some partial. Grading for those areas he completed properly and not to be treated as a cheater (someone who committed plagiarism intentionally).
The students are always
There was a consequence for not turning in the project on time, but the teacher acknowledged the effort and work your son put into it. 
