OK, that's a fair argument. On the other hand, Tito made the worst decision of his career not lifting Beckett when we went ahead 6-5, so you could argue that loss was on Tito.
Also, Beckett won Game 6 and then Lester lost Game 7 when he was outpitched by Garza for the second time in the series.
I'm just debating here, I don't even care that much about the matter any more. But you can't pin the loss of a 4-3 series on a pitcher who pitched badly in the second game of the series and should have been lifted with the lead anyway.