There are definitely some unhealthy aspects of surfing culture. Surfers will sometimes grow to feel they have a degree of possession or responsibility for an area. For some this makes them hostile to traveling surfers. But the vast majority will enjoy a chat and sharing waves. Regardless, these are local people who will probably be picking up litter on the beach and help a swimmer who is in trouble. They spend hours every day/week for much or all of their lives in an area surfing its waves. Usually the waves will be average and sometimes good. When it's good you feel like you've earned it... those few days a year. Most line ups have a hierarchy. The structure helps and the pecking order, while strange, means the older crew get more waves and the younger or newer crew get less. If you're new then it's a matter of introducing yourself to the existing structure. That takes time. Travelers usually have a few days or weeks. Sometimes they don't have patience and try to replicate their home environment wherever they visit.

I've been surfing for over 20 years and have never seen a surfer beat someone up. I have experienced bad vibes in the water and that's when I get out or move elsewhere.

Popular surf spots have signs up outlining some of the "rules" I listed earlier. It can help a lot. But things still get chaotic and many of these points also directly relate to safety in the line up.