I (naively) think the best comparison would be how we want such a company to work, one that protects the actors within it's ecosystem, especially de facto employees, and takes responsibility for accepting fraudulent transactions.

Paypal, Amazon, eBay and Etsy all behave the same here though. If an account is a vector for fraud, they want compensation or else they won't work with it anymore. Literally no one continues working with an account with $12k of chargebacks, that's the point.

The account with 12k chargebacks is not the freelancer, it is the person who employed them. Their account is the one at issue. This is not a normal chargeback from fraudulent behaviour on the end of the freelancer.

It is a chargeback because of fraudulent card misuse which should have been vetted by Upwork OR the payment provider. It is not the freelancers responsibility to do the payment or vetting. If it was their responsibility, you could cut Upwork out after the first transaction, but you can’t.

One of two people should be missing out here: Upwork for failing to verify the credit card or the actual persons bank for kit identifying fraudulent transactions.