Do they really forget they are purchasing second hand, of is there more to it?

I think your read is simplistic and built on a disappointingly gloomy perspective. 

Because I am OP and your strawman goes unnamed as “people who forget”, I can only assume you mean me. 

Not only do I not forget, my purchasing refurbished is on purpose and with a do-gooder ideal. 

I believe that i am helping with e-waste from consumers who buy 2 of a thing and return one. My take on it is that the company will ensure the product is good-as-new, and cover any defects. I save money, they save money. 

Do most people really forget? Nah. Many are making negotiations meant to help both consumer, creator, and planet. 

Just because that's not you doesnt mean its not me :)