We are being bombarded with the message to eat less 'processed food' so asking what that might mean and which foods it includes is relevant.
Most of us will agree on the definition found here:
Processed food refers to the products of food manufacturers; these products are literally manufactured in industrial processes.
Industrial is the key word. I can grind flour at home and bake bread but not with a mixer of 500rpm and 100 additives.
Any site with a more inclusive, favorable definition of 'processed food' is probably an industry representative
My opinion puts tofu at the same processing level as home curd cheese.