Why does the speaker say that it isn’t a fault to be shy?

Are you afraid to raise your hand in class, even when you know the answer? If you are, most people would say that you’re shy.
If you feel shy, you’re not alone. Nine out of ten people are at least a little shy. But however shy you are, scientific evidence seems to show that it isn’t your fault. You may have been born that way.
How do psychologists measure shyness? One way is by observation. They keep detailed records of people’s actions—like how often these people speak to others, or how long it takes someone to say hello to a stranger.
Another way to measure shyness is to ask people questions. The test only takes about 10 minutes. It asks questions like "Do you like going out a lot?" and "Do you have many friends?" People must answer either yes or no. These questions can predict how people actually behave in social situations. Suppose the test tells you that someone is shy. Chances are good that that person will act shy.
When scientists measure shyness, they’re really comparing degrees of shyness. In other words, when researchers say people are shy, they really mean they are more shy than others.