That's not the case. Buyers release and limit various remedies as against Stubhub in the user agreement but not against the seller. From the terms of service:
"Commitment to Supply.
By listing a ticket for sale, you are making a binding offer to sell that ticket to a Buyer who purchases the ticket for the price you have specified. When a Buyer accepts your offer by purchasing your ticket through our Site or Services, you are contractually bound to deliver that exact ticket for the specified price and within the required delivery timeframe. You are obligated to monitor your inventory and ensure all listings are accurate. Under no circumstances may Sellers cancel orders at one price and repost the same tickets for a higher price. Failure to fulfill your orders will lead to charges as stated in the Seller Policies.
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Buying Tickets.
You are responsible for reading the complete listing before making a commitment to buy tickets. When placing an order, you are entering into a binding contract with the Seller to purchase those tickets. Payment is remitted to StubHub and disbursed to the seller according to our payment policy. All Sales are Final. Except for cancelled events, you will not receive a refund for completed purchases. You cannot change or cancel any orders after the sale is complete."
The Seller policy specifies a breaching seller's liability to Stubhub but it doesn't limit in any way a breaching seller's liability to the buyer.