A longboard can sit further out and preemptively take off before a shortboarder possibly could, so shortboarders resent longboarders. Shortboarders can spin and go on really late takeoffs a longboard would never make and some people use this advantage to weasel in behind others who are already up and riding, and folks get resentful. Bodyboarders can catch anything that comes in, so some people resent them.
Everybody's looking for a reason to devalue other people so they can justify taking their waves. If my surfing is more rad/ pure/ soulful/ fun/ dignified looking/ cool/ important/ technically difficult/ (insert your favorite adjective here) than yours, then my way of surfing is a higher and better use of a wave than your way, so I deserve the next wave. In fact, I deserve every wave I want. Get out of my way, you kook/ barney/ wanker/ poser/ (insert your favorite derogatory adjective here). It's great moral apririn. I could snake you all afternoon long thinking like that and never feel like a selfish, mean spirited jerk. So could you. People do this because it works. They can be dicks and still sleep at night. But look where it leads us.
This is a lot like other kinds of prejudice. There are a lot of people in the world and we're all competing for jobs/ land/ money/ mates/ etc. and so we discriminate against other people we can define as a group and devalue, so our consciences feel better about ripping them off. If your skin is a different color it's easy, but people of the same color discriminate against each other on all kinds of bases (different religions, different culture, language, clothes, styles). We just can't seem to be homogeneous enough to avoid getting pigeonholed as "less than" by some group interested in helping themselves to whatever we are competing for.
Your attitude has a lot more to do with how easy it is to share waves with you than your equipment does. Mean people suck. Selfish people suck. They suck on land and they suck in the water. They suck on longboards. They suck on shortboards. They suck on bodyboards. Some mean people manage to suck with nothing but a pair of swimfins and a bathing suit on. It's not really about the equipment.
If I use this kind of "I am superior" attitude to justify being a selfish dick in the water, then I suck. If you do this, then you suck. It doesn't matter what either of us is riding. I think that more experienced and better surfers should get more waves, but they should get them from a climate of respect where others give them extra waves rather than from a climate of superiority and conceit where they take what they want and justify it with selfish, pompous arrogance.
Ride whatever you want, but mind your attitude.
I'm outa here,
Surfer Bob