My advice is that you never, never, never want to try to convince someone online by the claim to authority, I do this for a living.

A very large fraction of us do this for a living. Most people who do this for a living suck at it. The competent ones are painfully aware of that. Furthermore when they see an unknown person online falling back to argument from such spurious authority, it raises immediate red flags. If you are truly an expert, why can't you come up with something concrete rather than a vague catchall like that?

Therefore no matter what the temptation, don't start raising claims of being a professional. It only hurts your case.

Update: Tyop correction.