For good people to do bad things...

[Darwinian]

I think it's possible that you did. The minor addition of emphasis might make Padraic's point more clear: "Good people use religion to RATIONALIZE the most appalling acts. Without religion, they would find other excuses—such as 'the national interest'," which refers to the implied horrors of anti-religious regimes.

Now that my mind is starting to boot up I'll try to tackle this point.

You seem to be suggesting that good people would still do bad things without religion under the guise of alternative excuses. If this is what you are saying then I must disagree. It is of course entirely possible for good people to do bad things if motivated by any ideology but to say that they would 'find' other reason to commit bad acts suggests that they are just waiting to be bad and use any excuse to justify it.

This I infer from the following statement.

Without religion, they (Good people) would find other excuses

Suggests that they are just looking for an excuse to do bad things.

It is religious ideology, more than any other, that makes people commit acts that without religion they would simply have not committed at all.