What? Where? How? When? Why?

I survived highschool despite skipping Biology because Physics and Chemistry were easy enough to make it feasible.

After some more mature pondering I suspect I may have missed a beat. Does anyone have a good answer to the topic at hand? It feels like a subject that people take very for granted.

tl;dr
Normalfags will say plants are alive. Normalfags don't actually care about murdering plants. Normalfags say meat is murder and this horrifies them.

What is the line and where are the crossovers?