I do not believe this was solely the result of a marred desktop. If it is then I think the cruise line overreacted. Things such as the knarled wood documented in those photos surely happen at least a few times a year, and it is something that is easily fixed by a ship's carpenter with no loss of cabin usage. That can't be more than a few dollars worth of damage. Something else added to the final equation here.
I've been cruising on older vessels the past two years and my cabins have all had minor dents, dings, and scratches. I have never felt the need to document them in fear of being blamed for them.