Those that panicked and sell their coins immediately. People that continue to hold their coins will still see the price if bitcoin go up and get to ATH just as it has been in the past. But they are nit the ones that are affected the most. Those people that bought altcoins at a wrong price and the price started to fall. As bitcoin price fall, the altcoins prices will continue to fall which can significantly make the holders if the altcoins lose so much. What is more disappointing is that the altcoins may not increase up to ATH again.