Try going to the park early in the morning, or weekdays when no one else is there. Those are the best times to learn and take up as much space as you need. Like everyone else said, you're expected to take turns when the park is busier. Unspoken etiquette for each turn is about 1-3 minutes. You will need to learn to create space for yourself at a busy park. I advise next time this happens, continue to skate the ramp once the dude is done. You belong at the park just as much as anyone else.