You speak of active trading here. Yet, even CFDs can be traded long lony and long term.If you're trading with 3-5 trades, that can work so. But if you're taking trading seriously, you simply can't control each trade 24/7, so you would miss some of them and would lose money on them. Stop loss helps to avoid such issues. Otherwise, you can't control taking profit as well, so sometimes you can miss your profitable trades. So, it's better to set up them ALWAYS.
The essense of the ecnomics is that the value of top-performes (which is exactly what S&P index reflects) ALWAYS goes up. Yes, sometimes retracements happen. Significant retracements happen. BUt the fact is the historically AL these retracements have been covered by new uptrends. So the approach to risk management depends on the scope of your planning. Of course if you don't plan furthen than next weekend, stop losses are essential to control the risks. However, that's NORMAL to trade with no stop losses if you INVEST and don't plan to take the money out of the market any time soon.