Yes Romo is responsible for those INTs. But he was under pressure to perform. Romo needs a coach that can calm him down and to be able to keep him focused on the play at hand. Garrett doesn't do that. He doesn't have a relationship with Romo to calm him down and to make him comfortable.
Roger Staubach had some of those issues too. But Landry would call a time out and set things straight. They would strategies over plays that Roger would feel comfortable with and get him back into focus. It worked. However, Garrett just doesn't do anything what a headcoach is supposed to do. He doesn't provide the support and guidance that a coach gives to his QB. If only Romo had that kind of support or someone that can calm him down during big games. That is the fault of Garrett. That is why I think Romo deserves better. He seems to do everything for this team, including Garrett.
Thats why ultimately you have to look at the coach and say what have you done to help your QB? I don't think Garrett knows what to do. Thus its time to give up playcalling. Its time to have an OC here that can work with Romo. He needs a better coach than just Garrett. Garrett is not cutting it.