I think that rejecting the easy life of an hereditary peerage for the life of a Labour MP is proof enough of the man's commitment to the cause in which he believed.
As to his parents, wife, children etc, it would be naive to condemn him for his part in those relationships. Just as I think its wrong to bring up a child in a particular religious faith (let them decide when they are old enough to) it would be wrong to force his convictions on his family.
And to criticise him for having a private education is also naive - how many of us have our political views decided by the age one starts school. None.
As OC said, judge the man by his actions not by his circumstances.
It is not wise to apply the notion that things are either black or white - wisdom comes to those who acknowledge the many degrees of grey. Anyway, the black or white brigade have a different forum for that.
Sorry for being clumbsy with my words.... I know what I mean

*puts soapbox away*