Gambling plays a part, but I think it has more to do with the in-group dynamics of the crypto community. The Folding Ideas documentary on NFTs had an interesting segment on this topic.

Crypto forums use a lot of in-group language to communicate their shared belief of the crypto project (i.e. hodling, to the moon, etc., etc.) in order to demonstrate their belonging to the community and they summarily reject skeptics essentially as non-believers. It's a quasi-cult mentality but without a true individual leader. These forums then become echo chambers that serve two primary purposes: to continue purging skeptics and to repeat the crypto mantras over and over again without thinking critically. This is effective because it tends to attract people who may exhibit significant intelligence in other aspects of their lives. Where people really get into trouble is when they start thinking: "of course I'm too smart to get wrapped up in a dumb ponzi scheme, and this definitely isn't one."

This makes it really easy for the pump-and-dumpers to manipulate these people into making more and more risky crypto purchases.