There seems to be a push among many in modern evangelicalism to shun theology for more practical issues. The idea behind this, at least in some cases, is that theology tends to be divisive. For at least some of the participants in the current raging debate, this seems to be the underlying assumption. Doctrine isn't really all that important, and wrong doctrine is no big deal.
One comment I saw recently that I think epitomizes this type of thinking was this: And if I remember correctly the fruit of the Spirit didn't include "doctrine", but actually Paul exhorts us to "not become boastful, CHALLENGING one another...".
But this statement is somewhat naive, and based on a false assumption. The assumption is that spending time thinking about and discussing doctrine is a distraction from the real part of the Christian life. The problem with this is that theology really does drive methodology. Belief always informs practice, whether you are conscious of it or not.
Some examples may be helpful.
A Sunday School teacher believed in man's completely autonomous free will. He was asked the question about why we pray for the lost, if God can't really change their mind about anything. After thinking about it, he said, "Your right," and from then on he would not take any prayer requests for lost people. (I got this example from Phil Johnson's message on the History of Calvinism. If you haven't listened to it, I highly recommend it.)
What For example, you might think that the main problem today is the schools, and if people were just more educated, then that would solve many of the world's problems. Did you know that this testifies about your view of man, and about his sinfulness?
Or take apologetics & evangelism. What if you think that man's sinfulness doesn't extend to his ability to reason? If you believe that, a part of your methodology might be to reason with him, to educate him, and help him see the error of his ways. But if you believe that the Bible teaches that man's sinfulness is pervasive, to the point that it affects his ability to reason, you might eschew reason and proofs and choose a different method. This, by the way, is the heart of the different approaches to apologetics, presuppositional vs. evidential apologetics.
Here's how I see this applying to the present discussion. When someone, whether it be Michael Spencer or Doug Wilson, says that he considers Catholics his brothers in the faith, that affects his relations with them. If he is right, there is no need to evangelize them; at most, perhaps some work to reform their institutions. But if he is incorrect, then he (and anyone else who believes this) are neglecting sinners who need to hear the Gospel and be saved. They are incorrect, and it's for that reason that people need to stand up for true doctrine & good theology.
Does our theology need to be perfect to be saved? No, and thank God, because if it did, no one would be saved. In fact, all of us will be saved apart from perfect doctrine and theology. But that is no reason to ignore theology altogether, or to say it is unimportant.
So here it is. Poor theology leads to poor practice, while good doctrine should lead to good practice. This is why thinking about doctrine and theology are important--you should know what you believe because it affects what you do.
Remember that for the next time that someone says "theology & doctrine don't really matter, we just need to be Christians and love"--they also have beliefs that are driving what they do, whether they are conscious of those beliefs or not.