Who was the group that wanted Jonathan to conform?

Jonathan Livingston Seagull loves to fly. He loves flying more than any seagull who has ever lived! He spends hour after hour, day after day, week after week practicing his flying skills. He flies higher and faster than any seagull has ever flown. Jonathan “set[s] a world speed record for seagulls!” Against the advice of his parents and the other gulls in the flock, and against the voice in his own head telling him to be like all the other gulls, Jonathan does things in the sky that no seagull has ever done before.
“Why, Jon, why?” his mother asks. “Why is it so hard to be like the rest of the flock, Jon?” “See here, Jonathan,” says his father. “This flying business is all very well, but you can’t eat a glide, you know. Don’t you forget that the reason you fly is to eat.”
Nevertheless, Jonathan continues to practice flying every day, from early dawn to late at night.
After yet another day spent perfecting “the loop, the slow roll, the point roll, the inverted spin, the gull bunt” and “the pinwheel” and hurtling past the Breakfast Flock at “two hundred twelve miles per hour, eyes closed, in a great roaring shriek of wind and feathers,” Jonathan flies back to shore, and with “a loop to landing” and a “snap roll just before touchdown,” he lands gracefully on the beach near the rest of the flock.
Jonathan is certain that the flock will be “wild with joy” after watching him perform his aerial feats of wonder. “Instead of our drab slogging forth and back to the fishing boats,” Jonathan thinks to himself, “there’s a reason to life! We can lift ourselves out of ignorance, we can find ourselves as creatures of excellence and intelligence and skill. We can be free! We can learn to fly!”
In fact, “the gulls [are] flocked into the Council Gathering when he land[s],” and they have been waiting for him for another reason.
“Jonathan Livingston Seagull!” intones the Elder, “in a voice of highest ceremony. . . . Stand to Centre! Stand to Centre for shame in the sight of your fellow gulls!” Jonathan is being shamed in front of the whole flock “for his reckless irresponsibility,” the Elder says, and “violating the dignity and tradition of the Gull Family.” Jonathan can't believe it. He is being shamed for not being like the other gulls and for failing to conform to the mindless gull traditions “to eat” and “to stay alive as long as we possibly can.”
Jonathan protests that “for a thousand years we have scrabbled after fish heads, but now we have a reason to live—to learn, to discover, to be free!” But the gulls “[turn] their backs upon him,” and from that moment, Jonathan Livingston Seagull becomes an outcast “and [spends] the rest of his days alone.”