The flaw in Castle's logic is that no one is saying that Obamacare can be repealed while Obama is in the WH. Rather, repealing Obamacare is a long term goal and objective.
The Dems had no problem of advocating the repeal of "don't ask, don't tell" while Bush was in the WH. On issue after issue, the Dems never lose sight of their objective even when the answer is initially no. The just keep pushing and pushing until they achieve their goal. The Reps just adapt to what they believe is the immediate reality and don't have a long term strategy to roll back institutionalized socialism.
You wisely explain why the GOP is so ineffective on so many matters.