You berate rigidity. However, rigidity is actually a wonderful virtue when it comes to standing up for what is right. You seem to suggest that it is prideful. Nothing could be further from the truth. Moses was incredibly "rigid" on matters of principle, but the Bible says he was the most meek of men.
The highest and chief end of man is to glorify God. That is what truly matters in this life. It matters little if you save a thousand lives, but do so with a hateful and immoral spirit. If you wish to support moral causes, why not act in a moral manner. I suppose that requires a certain amount of rigidity doesn't it.
Your activism will never amount to anything if it is conducted in the absence of a fiercely consistent personal morality.