Why are we as taxpayers paying dues for this organization?

Its sole purpose is to find a way to extract more money from people who buy things under the guise of "Fairness." Formed in 2000, its "about us" page says:

"The goal of this effort is to find solutions for the complexity in state sales tax systems that resulted in the U.S. Supreme Court holding (Bellas Hess v. Illionis and Quill Corp. v. North Dakota) that a state may not require a seller that does not have a physical presence in the state to collect tax on sales into the state"

First, I should point out that compliance will NEVER be as simple as whatever their ultimate outcome is touted to be.  The burden on small business increases yearly with nearly every law passed by our state legislators, and especially so with the efforts of the US congress and administration.  Unable to absorb new duties/responsibilities as designated by all the elected busy bodies without significant time for compliance measures WILL destroy small business in America; resulting in higher unemployment, and deepening resentment for overreaching government.

For a little deeper look into this issue, and about the organization above go to Grass Roots In Michigan. At one point she mentions that:

"SSUTA moves towards taxation without representation in two ways. First, state lawmakers' authority regarding significant portions of state tax codes is given to an outside entity, moving representation further away from those states' citizens. Second, businesses outside of such states are subjected to taxation - not limited to, but including sales / use tax -  but have no representation in those states' governments."