You make a good point!
Christians must live by the Word of God, and use the facts contained in it when explaining salvation, God etc. However, a Christian just spewing out scripture but not having any actions to back it up is doing a dis-service to the Kingdom of God.
But, you also cannot condemn a Christian because they use scripture to back up everything they teach. That is a good thing! If actions or "Christianity" doesn't line up with scripture than it is not of God.
John 1:1-2
In the beginning was the Word, and the Word was with God, and the Word was God. 2He was with God in the beginning.
That is a very profound scripture! Which causes me to have the utmost respect and reverence for the Bible. And, causes me to try my utmost, to have my life line up scripturally, to be led of God, and filled with the Holy Spirit.
Again I guess, it comes to balance.