~SNIP~
You are definitely right in some context and when we try to look at what you said from some special angle, winning can not be that harmful unless it get loses involved, so in the end, it still all boils down to loses, loses is the chief orchestrator of a sad life filled with regret and depression.
So let me just say that aside maybe being over joyed and getting oneself hurt or getting into some kind of trouble, I really do not see how winning can ruin a person through gambling, no body gambles to lose money, we all gamble to win, and it is expected that when we win, no matter the amount of money involved, we should make good use of the opportunity, when a gambler is opportuned to win but ends up not making good use of it, we cant say that winning destroys him or ruined his life, the gambler himself ruined himself by not being sensible well enough to make good use of the opportunity he was given.
Absolutely untill there is said to be losses, there would be no harm in winning because all you accounts is stacking of profits but the question is... Are you staying consistent playing even while you have made several wins? Of course it would result to reverse be the case because you definitely won't keep winning.
And to the greeds once a lost would want to chasing recovering which is where I would concur that architects the harmfulness as a result of overjoy and lost of self control.