they cant tax for gambling (well they can but its then too complicated surely).
what happens if i win. i pay tax on the win? .. what if i lose? can i claim my tax back?!.. its hardly fair to charge me tax when ive just lost my money anyway.
the whole point to betting etc, is its calculated gambling.. ie i know the odds, and i know what i expect to walk away with should i win.. i dont want to have to calculate how much i need to put down (inc tax) and then have to workout how much i'll earn after tax deductions from winnings etc.. it shortens the income potential so why would i bother? its the bookies that never lose that should pay additional taxes if taxing betting is required. im sure they make more than enough!
i dont bet myself. but i do trade a bit (spread) which is also tax free due to it being classed as a "gamble"

.. i'd be pretty f*kd off if i had to pay tax on that being as ive taken the risk to do it with my own money, then anything i make (or lose) should remain mine fully - plus we all have already paid income tax on the money were all betting with which could vanish in a flash if we chose wrong. thats enough of a risk without giving anything to mr tax man.