(Apparently this makes sense because if gambling wins were to be taxed then gambling losses should also be deductible, and since gambling is inherently a losing proposition, the tax authorities would lose more than they gained. I don't really buy this argument since they could just tax winnings and offer no deductions, but hey ho.)
I don't think this would make sense. If I walk into a casino with $200 and then proceed to lose $100 and win it back 10 times, then I lose it all and walk out, that tax law would say I had "won" and had to pay taxes on $1,000 even though any reasonable person would say I had actually lost $200.
In practical terms, I think it would absolutely ruin gambling addicts. This makes it effectively impossible to actually net profit, and I'm doubtful they'll stop.
I googled because I was curious and found an article about it [1]. It's similar to PayPal/Venmo/etc. Once your winnings meet certain criteria, the casino has to give you an IRS form (W-2G) and they presumably send another copy to the IRS.
The withholding part isn't super clear, but I guess under some circumstances they also withhold 24% of those winnings to pay federal taxes.
1: https://www.hrblock.com/tax-center/income/other-income/gambl...
Welcome to the modern Western society, in which employees have been reduced to litigation-avoidance automatons. No wonder so many people hate their jobs, stripped of any power to help or even just follow common sense.
I know in some lotteries and sweepstakes they tax the pool, and so the winnings are tax free to the winner and the taxman invisibly still gets his cut.