Surfing and swimming are two of the most aggressive and competitive sports on the planet. Don't kid yourself.
I've gotten into arguments and a near *fist fight* once but the guy was cutting into my path on purpose.
1) There are jerks in every sport and if it's not the competition it's the localism. Get a stiff upper lip and suck it up.
2) The main reason people try aggressive manuevers is to try to intimidate you into moving and/or leaving. You have to be willing to talk, give them some room, and take turns.
Go really early or really late. Offer to leave for awhile and come back. That's actually worked for me. They'd rather have you do that then stay and share.
3) You thought surfing was about love and peace. It is and it isn't. Newbie's struggle with that because they have no sense of the community as a whole. If I asked you to explain the phrase "Eddie would go" you probably couldn't. That will cost you a lot of respect.
There are people like yourself who just want to have a good time and not take things so seriously. Do a little networking,
meet some locals, and read more about surfing. Expect tension. Acceptance takes time.
4) Surfing is about respect. At any point did you try to talk to these people? Locals always have the right of way.