I agree with you, if I will be taxed for gambling, then I'm definitely going to quit because I believe they will not join be in bearing the losses when one comes, like you did mentioned, it's a hobby so why tax a hobby? To me it makes no sense. May country don't task gambling profits as gambling here is seen as a game played for fun so the government don't really have much to do with it, basically, they task the casinos and not the players.
Governments are carrying such large debts that they are looking for any venue they can get some additional cash, and soon enough the countries which do not charge any tax for your gambling profits may change their tune and go after gamblers, after all there are many countries in which any gift you may receive above a certain amount has to be declared as income, something that is completely ridiculous as well, since most people receive gifts on their birthday or another important date, and yet the governments want a cut from that money too, which does not make any sense but it shows you in how much trouble they really are.