There is no coercion. Your first wikipedia link says "[c]oercion involves compelling a party to act in an involuntary manner by the use of threats." Saying, effectively, "I no longer wish to be associated with you" is not a threat.
It's also not extortion. Your second link says "[e]xtortion is the practice of obtaining benefit (e.g., money or goods) through coercion."
Again, there is no coercion, and advertisers choosing not to advertise on his platform are not "attempting to gain benefit" at all. They are trying to avoid what they perceive as harm to themselves.
He is not "off by a hair," and neither are you. You're both miles away from even being able to see the ballpark.
