It's that word "good" that makes it a true statement. You can't be peddling the outrageous stuff the left peddles and still be considered a good Christian, by any Biblical standard anyway.
Hmmm... Interesting viewpoint. So, the only "good" Christians are those whose political beliefs are somewhere to the right of the US Democratic party. Which would exclude just about everyone in every other nation with a Christian majority.
Anyway, it is more interesting that one's Christianity can be adjudged "not good" based on political beliefs. Methinks you presume a bit too much.
Ever look into Mother Teresa's politics?