Cooking non-Kosher

Question

Dear Rabbi, On numerous occasions you have mentioned that it is prohibited to cook or otherwise gain benefit from any non-kosher food. My understanding - please correct me if I am wrong - was that only certain foods, like hametz, meat&milk, yayin nesech, etc., are prohibited for benefit, whereas other non-Kosher foods are OK as long as they aren't eaten. Many halachot in Yoreh Deah seem to be based on this principle. If we are prohibited from benefiting from any non-Kosher food, how do we understand the distinction between, let's say, basar b'chalav and other forbidden foods? Thank You and Shabbat Shalom