They are doing it because of their fear of losing more money ,
They bought it because they think that they could gain a profit from it and they ended up losing more.
True, they don't want to lose too much or they panicking. I think those person is a beginner, they have no enough knowledge in the market instead of earning money opposite is the result.
In crypto world, to earn profit we need to wait the right time for the price, patient and experience are key to earn a bunch money.