If you'd like to isolate individual pollsters, you may do so. The "remove bias" button adjusts all polls to a uniform bias. Intellectual honesty compels me to point out that we don't actually know that the average bias of the polls is correct, but at least it's consistent.
If you have thoughts or questions (or wonder about my choice of pollster) feel free to contact me directly at drdavegoldberg@gmail.com.
I've also done a more detailed discussion at my blog: The Progressive Physicist