Is the argument that there should be no sales tax, or that online businesses should be exempt from it? Alternatively, is there some specific compliance issue or formulation in the proposed legislation that is poorly thought out? I'm genuinely curious, as (in principle) the fact that online businesses have been exempt from sales tax largely strikes me as an anomaly and not some new standard.
Mail-order catalog businesses, which have existed for decades? You only pay tax in jurisdictions in which you're physically based (for an internet startup, this would be wherever you're incorporated). This axiom has held in US tax policy for about as long as there has been US tax policy. Kinda ties in with that whole 'no taxation without representation' thing. Edit: for clarity .
No, it hasn't. You have to have a business nexus to be subject to taxation, but both physical operations and incorporation (which are often different states) form a nexus, as do certain other activities.
Before, even with mail order, remote operations choosing to actively solicit business in a state without physical presence were never a large volume of retail; with the internet, that's changed, and it makes sales taxes create a perverse incentive to avoid locating in the states where most of the business originates.