Why do gamers try as much as possible to avoid graphic cards that have been used for mining before?
Think of it this way,
Would you buy a car whose previous owner used to drive the shit out of it and has higher mileage, or would you go for one with a lower mileage if you have some extra cash to spend?
The cards used for mining run almost 24/7 so while some people wouldn't care so long as the cost was friendly, if I were in the gamer's shoes, I would try looking for other options if there were any.