If the weatherman says it's warm today, some will say too hot, some will say too cold.
There is no internationally recognised unit of left/rightness. You will always need to apply your perceived bias to anything like this. Don't expect them to match exactly what you feel.
I agree with your analogy.
I too would consider my personal opinions prudent and middle-of-the-road but unlike AllSides.com I do not run a website whose mission statement allegedly is to be transparent about media bias.
