Kresser mentions that the proposed mechanisms thought to be behind processed meat causing cancer are N-nitroso compounds, heme iron, TMAO, Neu5GC, and heterocyclic amines formed from cooking.
And when it comes down to the specifics of why meat is bad, compounds in meat are often investigated — things like heterocyclic amines, TMAO, Neu5GC, Arachadonic acid, and the list goes on.