Requiring gambling winnings tax is actually not proper thing, as I have said several times in other threads regarding winnings tax, the government should only apply it to casinos as form of tax for operating permits.
If I'm not mistaken, government doesn't tax gambler per se, it is still the casinos that they put a lot of tax. Except maybe if you won the local lottery, that's where the government tax comes in because it's obvious that they run it.
Likewise, I have seen many governments enact regulations and taxes on the gambling industry but they all target the casinos because they are in business. This is also the first time I have heard of the government taxing gamblers, which is really strange to me.
Regulations need to be fair to a certain extent, otherwise it will be counterproductive for the government because if it is too strict and extreme, I think casinos and players will find ways to evade taxes and circumvent the law. I think governments understand this better than anyone.
I don't know which country does this, but if I lived there, I would make sure not to use fiat casinos or local casinos to avoid winnings tax, it is better to gamble on foreign gambling sites that can provide me with security, comfort and various other benefits.
I think the government of the country where you live really doesn't care about its citizens who like to gamble, there should be lot of consideration before policy like this is made official, especially since it doesn't provide any benefits to the people there.
I lived in a country that have big traditional base casinos, but we are not tax when we won, they are the one paying the casinos. However, as per protection from online casinos, I do no think that there is enough regulations from many countries. And even if you file cases about a certain casinos, I do not know how it will be handle as obviously, it's cross border and laws are going to be that complicated to go after them.
Frankly, these regulations don't make much sense and we shouldn't put too much faith in them. Simply because the government does not have the time and resources to resolve lawsuits or disputes that only involve a few hundred dollars or a few thousand dollars, they will prioritize resolving larger value litigation. So we should protect ourselves first instead of waiting for the government to protect us.