Ah this is a classic language misunderstanding. "Isn't necessarily" means "possibly not [thing]" or "doesn't have to be" or "may or may not be" but doesn't have much bearing on probabilities.
That's how people usually use that term in English anyway.
EDIT sorry didn't mean to dogpile. I just saw that a couple other people already replied.
That's simply not true. I agree that it seems to be social anxiety depicted but you misunderstand that phrase. That's basically just saying it could be something else, nothing to do with likelihood.
They are and they do, but this example is extreme. Having been on both sides of this, I'd say no one should have to live their life in fear of every little interaction. It's exhausting, and you will never succeed in getting every person to leave you alone anyway. But this doesn't have to be "the way it is." You can actually change and make your life easier. Sometimes it takes help and a long time, but I believe most people can do it if they really want to.
I don't even have anxiety and I think this is relatable. It's not even necessarily fear, but maybe not having the bandwidth to be social in that moment.
Do you think we should treat people with crippling anxiety by telling them that their anxiety is crippling any time they post on the internet about how crippling their anxiety is?