The beaches in front of the Waikiki hotels were more crowded than this, but then the waves were much smaller. It's best to avoid going out if your skills aren't such where you can surf a safe line in between all the people on crowded days. If you're starting out, stay away from other surfers or go out at less crowded times. The longer sup boards are very hard to turn if you're new to stand up surfing. Before I take a wave, I look to see if someone else is planning to take the wave and check to see if the area I will be surfing into is clear, if not, I don't go. It's simply not worth colliding with another surfer. At Waikiki, we had swimmers snorkelers, surfers, sup'ers, and kids on inter tubes floating everywhere, so I took less waves.
And there are rules of the road, or rather 'Surfers Etiquette' at all breaks worldwide to avoid collisions or creating unnecessary tensions. I'd recommend reading the rules to get an idea on how to surf safer, HERE.