Some miners cannot afford to hold. They have to sell and pay for electricity bill.
I never understood this argument, I have bills to pay too and I buy coins not knowing if I will profit on them in a day or in 3 months, that is why it is called investing.
If some miners want to purely mine for a daily profit and not invest, I don't begrudge them, but I know they will also cry when the price shoots up too.
You almost answered your own question. You BUY coins, you don't mine. Also miners do not care what the coins do, they mine for immediate profits not speculation on price movement.