I'd rather many people earn ten dollars an hour under the protection from a corporation by a union than one guy "opt out" of the union, leading more and more people to opt out of that union and... quickly... no one having protection from that corporation and all quickly being fucked.
That union needs to keep functioning to keep protecting you from the company you work for and, yes, you have a responsibility to contribute to the continuation of that protection through union dues.
To say that you are being "extorted" by the union is as if to say that you walk into a grocery store, walk out with ten dollars worth of food and... when they tell you to pay for that food or they're going to call the cops, you're being "extorted" for ten dollars.
The service of protecting you from the company that you work for and that would exploit you endlessly if it could has already been rendered by the Teamsters, brother.
You are trying to walk out with the fruit of that labour without contributing to it.
I know that you got some kind of Stockholm Syndrome hard-on for big business, believing that if you follow your captor's every word he will protect you and make you like them and shit, that if you play the game by their rules, you'll be allowed to win too...
But it ain't that way.
The business wants as much out of you for as little as humanly possible.
The union protects you from that.
Your dues make that union possible.
Deal with it, delay some gratification, man, this is how it works.