I believe that Bitcoin miners have a moral obligation to return blatantly abnormal fees once apprised of the situation
A moral obligation to fix someone else's mistake. Hellz no.
Granted, it would be a nice gesture to return what in this case seems an obvious error. If I were the miner, I would like to think that I would return the overage. But 'moral obligation'? That's crazy ass special snowflake shit.
Life is dangerous. Live accordingly. Don't expect others to clean up your messes for you.
There's nothing crazy about moral obligation. Life is not dangerous or there wouldn't be 7 billion humans on the planet - you're simply creating a false narrative. There's nothing dangerous about this particular predicament nor should it be considered a mess, an honest mistake has been made that merely requires honest action on the part of the miner (in this case Antminer) to remedy. Hellz yeah!
We are all making mistakes, because we are not perfect and no one is perfect. And asking something back is not that easy, becuase people do like money, and 2.5 btc is a big deal. So, you are lucky if they are going to give it back to you, unlucky you if they don't. We, all the people in this world are the ones who are dangerous, and not this moral obligations.
We are all animals, animals in our own way, animals that lives in ourselves is the one who made us dangerous and making choices good or bad is up to us, and making big mistakes are the one taught us to be more careful next time, especially sending bitcoins.