There is still a stigma against social anxiety... which reinforces the anxiety. People experiencing it will usually talk about "anxiety," because everyone knows this is something not to beat people up for. They almost never call it "social anxiety" even when it obviously is.

You would think most people would be sympathetic, given that just about everyone experiences social anxiety here and there. But that expectation is just one of those fallacies.

If you tell people about your social anxiety, or you tell people you grew up in a dysfunctional family, expect to feel a bit avoided afterwards. People don't mean it, usually. But it's something about human nature.