The truth is sliding doors don't exist on a lot of cars simply because small-penised people associated them with minivans and get hot and bothered. Most SUVs now like the Explorer, Honda Pilot are really just AWD minivans except lacking rear-sliding doors. A Sienna AWD with sliding doors is a girly minivan but a FWD Highlander is a manly SUV.
Maybe you should be looking in your own shorts rather than making judgments of others'. Sliding doors don't exist on passenger cars because of packaging. There is no room for them. Their sloping roof lines and curved bodies do not provide anywhere for the slider to work, period. Not to mention a 4 door car, that simply wouldn't work at all.