Well, I see you don't have the brain to figure it out, so here you go.
What difference does it make whether or not all teachers hired a hitman,
you ask. Well, IF you could follow along, you'd see that Greg asked
"what is up with ALL OF THESE MURDERING TEACHERS THESE DAYS", notice,
the word "ALL". So, the difference it makes is in the insinuation that
ALL of the teacher murders were from hired HITMEN.