People who diagnose mental disorders on the internet are lying

You ever hear these nerds online throw around the words "psychopath,sociopath,narcissist,depression,anxiety" like they are some type of psychologist. Always hear some nerd say "X is definitely a psychopath","my ex was a sociopath narcissist",or "I have depression and anxiety but I never saw a therapist" about people they don't like or themselves. There's people that go to school for psychology who still aren't able to diagnose mental disorder with 100% accuracy yet it turns out everyone online has a psychology degree. All it takes for them is to google "x mental disorder definition" and now they're an expert on it and will stick that term to whoever they don't like. Public figure,athlete,ex,family member,themselves etc all have a mental disorder.
gets a little nervous in an interview or when meeting new people "I suffer from anxiety"
No you don't dickhead. Everyone gets nervous at times. You're just a normal human unless you're excessively nervous almost all the time(which none of these people are) to the point where it's damaging your life