Why does Holden not want Phoebe to come with him out west at the end of The Catcher in the Rye?

doesn't
wantto come out west with him because he realizes he is putting his fantasy need for escape
ahead of her real needs to live her life as a healthy, well-balanced child. He remembers how
very excited she was, when he visited her at home, to tell him about her role playing Benedict
Arnold in her school play. Holden knows she is brimming over with excitement about acting this
part and that she wants him to come see her in it. He knows that if he runs off, even taking her
with him, that he is being no different from her father, who can't come to see the play because
of his own prioritiesand no better than a Benedict Arnold himself, betraying her. He realizes
that she needs, overall, to be in school. He is selfish if he takes her away or allows her to
sacrifice her needs to his needs. He says to her, being uncharacteristically harsh

"I thought you were supposed to be in a play at school and all
I thought you were supposed to be Benedict Arnold in that play and all," I said. I said it
very nasty. "Whuddaya want to do? Not be in the play, for God's sake?" That made her
cry even harder. I was glad. All of a sudden I wanted her to cry till her eyes practically
dropped out. I almost hated her. I think I hated her most because she wouldn't be in that play
any more if she went away with me.

He thinks that he
would hate her because she wouldn't be herself if she ran awaybut primarily, he means he would
hate himself. He realizes he is dragging her into his spiral of self-destruction. He comes to
his senses and tells her that he is taking her back to school and that he is not running away.
He is behaving like a responsible adult here, not like a self-centered adolescent, showing he is
growing up.