I think you are judging the issue absolutely right. As a nation, we have not learned to consider issues rationally and without any political idealogies, but believe in blindly raising a flag against this or that. If we had truly matured as a democracy, in this case, either Congress should have convinced the left, or Communists should have satisfied themselves or convinced the Congress not to go ahead, and together they could have examined the issues closely with only the national priorities guiding their decisions, and very importantly should have put up a common face up before the world with one single decision - yes or no! But what happened was that the UPA government and the Leftists engaged in a timeless bout of shadow boxing, throwing up punches here and there. In this game, "Jo jeeta wohi Sikandar"!
Problem: Parties poles apart in their idelogies can never work together. Solution: Elect just one party or the other to Govern - we sink or swim. Any day a better option! Also do not encourage pre or post-poll alliances, it is all a hog wash.