This is a very common trait among human beings, to share the success but not the failures that lead to that success, as an example if you take a look a social media most people share the pictures and experiences of everything that went right with their lives, this gives the impression that everything is great in their lives but they do not share the bad moments, and as such the way they present themselves is biased, and something similar could be happening here as we have no idea how many losses were necessary to achieve those results.
That is true, because it feels good for the self esteem of people in general to share their success stories in public. It makes people feel important, special and unique towards everyone else around.
And in this case, if the story is legit and this gambler is on positive profit, I must say he is really a special one who is among the small percentage of victorious gamblers able to thrive betting. Moreover, considering how much money he risks on his bets, this achievement becomes even more unique and magnificent.