I completely disagree with you here in your final,analysis. While I agree that bias can play a role in scriptural understanding it doesn't have to. True scriptural scholarship strives to let scripture speak for itself. What does the text say? To do otherwise places our philosophies ahead of scripture. What you seem to be saying here is we can never really get the true meaning of scripture or really understand it because our bias always gets in the way. If that is true then it's just pure luck if we happen to get it right.
What I find, when it comes,to scriptural understanding, is that our bias usually comes from an outside source. Perhaps a book we read or a science we follow.
But real biblical scholarship takes proper hermeneutics and exegesis and applies that to,scripture and lets,the text do the talking. As Paul said
Every scripture is inspired by God and is useful for teaching, for showing mistakes, for correcting, and for training character, so that the person who belongs to God can be equipped to do everything that is good.
2 Timothy 3:16-17 CEB
http://bible.com/37/2ti.3.16-17.CEB
It is all inspired and useful. How can we possibly teach, reprove and exhort if we cannot say what we are saying is correct? If,all interpretation is biased then we have no ability to truly understand or use scripture correctly.
Our goal when studying scripture should be to strip away our bias and let the word,of God transform our thoughts. Let scripture strip away our bias and let our thoughts conform to what the bible says.
Don’t be conformed to the patterns of this world, but be transformed by the renewing of your minds so that you can figure out what God’s will is—what is good and pleasing and mature.
Romans 12:2 CEB
http://bible.com/37/rom.12.2.CEB
Therefore, if you were raised with Christ, look for the things that are above where Christ is sitting at God’s right side. Think about the things above and not things on earth.
Colossians 3:1-2 CEB
http://bible.com/37/col.3.1-2.CEB
We are to set our own thoughts aside and think on the things above. How do we know what the things above are? They are written i in Gods word. All scripture is inspired. When God says he created in six days it means he created in six days. To believe otherwise is putting biased thoughts ahead of what it says. Instead of thinking on the things above and having our thoughts transformed we are being bound by our worldly fleshly ideas and thoughts.
You are right it can be a battle. But it's a battle that can be won. Not all the time every time, but increasingly so as we seek,the truth of the GODS word.