Well your statement is not much clear, i think all private btc mining operations do reinves their part of earnings back into mining equipment and stuff so all these businesses are actually helping the market, as if they will not reinvest their business will become slow and end up yielding no profit due to increasing mining difficulty.
I think its not mining operations the concern should be. It's competitors of Bitmain at least that's how I see it.
Mining operations would just get profit and buy more machines. If Bitmain is the only competitor and Bitmain actively reinvests in coins, then its positive. If there are many other competitors, it's not clear how they will use their funds. If they increase scale, a lot of earned money goes back into infrastructure and fixed costs which takes away from Bitcoin. Bitmain already has much of this in place already, so I would assume they could save the cash to buy more coins or find new crypto related outlets to invest in.
I'm all for the private miners though.
