It still amazes me how much confusion there is over this.
1.) eBay isn't handling sales tax on behalf of sellers, they handle it on behalf of buyers and the states.
Sales tax is and always has been the buyer's obligation to pay to their state - the seller (or now the marketplace) has simply been required to facilitate that collection in certain circumstances.
For those who claim they would rather eBay charge them fees for this "service" than have to do it themselves, I would ask how many of those many states and jurisdictions would you legally be required to collect for if it wasn't eBay's obligation under Marketplace Facilitator laws?
My guess is for the large majority of sellers it would be 0-1, just like it was previously, with a few having more than that if they are large companies with physical nexus in multiple states or make enough sales to each state to pass the economic nexus thresholds.
If you don't know what economic nexus is, here's a breakdown, but generally speaking most states you would have to have a minimum of $100,000 in sales to that state in a year.
https://www.avalara.com/us/en/learn/guides/state-by-state-guide-economic-nexus-laws.html
2.) Everyone else does it...kind of.
PayPal and credit card processors charge their fees on sales tax - usually in the ~2-3% range.
Etsy charges their 2.9% payment processing fee on the tax amount, but not the 6.5% commission.
For seller fulfilled orders, Amazon does not charge any fees on Amazon collected Marketplace Facilitator taxes. If the seller has direct tax collection obligations and opts to use Amazon's tax calculation service, a 2.9% processing fee applies to the tax amount only, separate from Amazon's referral fee on the item price + shipping - and even this will be pretty much a moot point as the few states with sales tax that didn't have Marketplace Facilitator laws before finally get on the band wagon.
So yes, it's fair to say others do it too, but I also believe that's an argument of false equivalency as ~3% is very different from the variable percentages here on eBay which can go as high as 15% in some categories.
3.) eBay has to cover their cost of compliance
Many states offer incentives that provide credits or rebates for filing sales tax early or electronically. These incentives may allow the merchant (or marketplace) to retain a small percentage of the tax collected, which can help offset the costs of compliance.
Presumably eBay would at least be eligible for the same incentives as any seller, if not possibly even more favorable terms - like the sweet 15 year tax sharing deal they cut with the city of San Jose to designate all sales on the site that ship anywhere in California as having occurred at eBay HQ, thus allowing the city to collect the local tax that would normally be spread out amongst various cities in the state where buyers actually reside.
That means in California, other cities aren't even getting their share for infrastructure upkeep or anything else the local portion of the tax would normally be used for.
San Jose gets 1% of all CA sales and eBay gets a kickback of 30% of anything they collect over $5 million a year.
https://news.bloomberglaw.com/daily-tax-report-state/no-strings-attached-tax-deal-shows-depth-of-eba...
If other companies and payment processors can cover their costs of compliance at ~3%, not to mention a tax sharing deal estimated to be worth ~$150 Million...eBay absolutely does not need to charge the full FVF on sales tax just to cover their costs.
Can they do it? So far it would appear so since it hasn't been successfully legally challenged.
But that doesn't mean it's unreasonable to question the ethics of it or to feel like it's a bit sneaky or slimy.
