Most people don't make 20 stock buys a day, but it is essentially the same thing. I may be comparing spy apples to granny smith apples, but it wasn't really meant to be. You are making an educated guess on what the outcome will be, and putting money on it. Whether it be futures or facebook stocks.
Do I think there's as much addiction to stocks, no, and generally you aren't risking your rent each month on stocks, but they can both ruin your life. Same as horse betting, same as slots, same as black jack. There's no reason to police every aspect of peoples lives when other risky behavior is completely legal.
Sports gambling is legal here and people seem to be just fine. In fact the government is making good money on it.