I had a ticket from KBP to LHR via FRA for 03/26 and back on 03/29. Lufthansa canceled all flights from KBP 10 days before I was due to travel. Since I booked via Expedia I tried calling them to ask for a refund but it was impossible to get through, so after 2 weeks of trying I gave up, called my bank (Citi) and asked if it was OK for me to initiate a chargeback due to it being impossible to contact the merchant. They said that I should go ahead and so I did.
If you initiate a chargeback without even communicating with the merchant (LH) and its agent (Expedia) the chargeback can be contested by the merchant. The advice Citi gave was wrong. The chargeback always has to show that you tried your best to resolve the issue with the merchant and they did not perform their end of the contract.
You can debate how the airlines are justifying themselves, but essentially they are showing that the consumer didn't attempt a resolution and that is all the payment processor needs to decline the chargeback.