What makes Abbotts' actions unacceptable is the fact that she was outspoken in her attacks on both Tony Blair and Harriet Harman for their decisions to privately educate their children.
She made no attempt to defend her choice;

"It is inconsistent, to put it mildly, for someone who believes in a fairer and more egalitarian society to send their child to a fee-paying school.
"I had to choose between my reputation as a politician and my son."

I'm not against choice but Ms Abbott was elected because of what she said she stood for.