What is "taking accountability" supposed to look like in this case?

As an aside, trying to enforce some cultural more without the backing of senior leadership is a waste of time. You should probably follow your colleagues example and get a better return on your time with Claude and stop caring. If you are the only one at your company who cares and you aren't the largest shareholder I have to ask under what economic theory you are operating. Unless you work for a charity or something you should probably either find a new job or stop complaining about the relative luxury of being handed a fistful of money just to be able to say "Claude wrote that".

Apparently no one at your company cares, so why do you?