Without a doubt when people are talking about a dump they think of a regular drop in the market in which there is still a possibility for the coin in which they invested to recover, however the dump of Luna was different.

If someone had most of their capital invested in Luna and was even gambling with it then what happened affected them to an incredible degree, as the coin crashed almost all the way to zero in a single week, and as such any moment of hesitation was a moment in which the price kept dropping and it was making more and more difficult the decision to sell, which is why so many people that bought Luna for a high price decided to not sell thinking the coin will recover, only to be proven wrong and losing any chance of ever recovering their money, which without a doubt affected their gambling as well as now they had no money to spare at all for the activity.