OK, so I'll give you that she did say what she did was 'intellectually indefensible'. Going through that interview, she seems to be saying that at the time, she sent her son to a fee-paying school because the local schools were not very good. She also seems to imply that because the Labour Government subsequently improved the state of schooling locally, she would not now need to make the same choice. That appears to be perfectly consistent with a belief that the Government should make state schooling good enough that people shouldn't need to send children to fee-paying schools (which I
think is roughly what Diane Abbot's beliefs are) - so if I'm correct, by itself that doesn't seem hypocritical. Besides, describing your own actions as 'intellectually indefensible' sounds rather more akin to an apology rather than to hypocrisy.
There's an interesting comment on
Wikipedia:
That seems to imply that Diane Abbot was doing what her son wanted - which might not have been what she herself wanted - in other words respecting the opinions and wishes of someone who possibly disagreed with her. That would definitely
not be hypocrisy.
So the only thing we are left with is the issue that Diane Abbot had previously apparently previously criticised other Labour MPs for doing what she then did. That may be hypocritical - depending on precisely what she said, or whether she still stood by her comments. I can't offhand find any reference to what her exact comments were, but the gist I get reading through the Mirror interview is that she seems to be regretting those comments whatever they were, but not being willing to say so. If so, I'd interpret that as a case of being too unwilling to admit mistakes rather than a case of hypocrisy, but I may be wrong.
FWIW, I don't on the whole think very highly of Diane Abbot. But in this particular case, it looks to me like the accusations of hypocrisy against her were not based on a full analysis of all the circumstances, and were probably not entirely fair.