Taxation is fair exchange??
I think it is more like tribute.
What you are receiving "in exchange" is protection from a racket.
I agree with you, some taxes are tantamount to an extortion racket.
Why is that fair "sometimes"?
Some taxation I view as fair exchange, for example I am happy to contribute to the refuse collection system and maintenance of public grounds in the town I live, the firemen, police and ambulance services etc, the local council tax I pay toward that I view as fair.