What are the specific dangers associated with Grignard reagents?
I have to disagree your position entirely. 

Every chemical has associated hazards, with even the most unassuming chemicals having the potential to cause severe harm if not fatality. 

However, the actual risk to the chemist is often severely minimised by taking sensible precautions, understanding the hazards, and working under a controlled set of conditions.

The whole purpose of organic chemistry education, especially the purpose of organic chemistry labs is to teach students how they should safely handle chemicals, not to tell them that they're too risky.