Yeah I think my point was more that a blanket ban on rebasing is too rigorous. I agree that once you want to integrate B and C (or both into A), a merge is usually the best way to do it - and I think that's what TFA was actually referring to.

It fails to consider the case, however, of rewriting B's history internally, not as a way of integrating with A or C, but as a way of making its commits clear. Afterwards, you'd still do a merge of A into B and then merging B back once you see that's successful.