Rationalization is usually said when the conclusion comes first, and the "reasoning" latter. First you decide what you think, then why. This "reasoning" is considered suspect, and called a rationalization.
My rationalisation is just what I think makes it rational. No negative connotations here. "How do you rationalise that, then?" is where the doubt creeps in.
I think I just presumed someone blogging about being discriminated against for political views would have left-wing political views.
I didn't really realise US academia was so skewed left politically; completely misread the subtext.