While this person is obviously an extreme gambler, that doesn't mean that it's wrong for them to be betting on things. It might well be that this person is wealthy enough to genuinely afford to lose such a large amount of money.
Yep, when you are a high roller, you can lose big but you also have the chance to win quite big in a fast manner with some luck.
These high rollers usually have a large enough balance to to wager at a higher level. You see this all the time in normal physical casinos as well. For more wealthy people, it takes higher stakes to get the same adrenaline rush.