Oh really? So you think that flight crew should be "obssessed by customer service"? No, I don't think so. It's important, sure, but it comes after safety.
In the context of this thread, I don't think that these two are mutually exclusive. I'm struggling to see any way in which safety is compromised by telling people why their flight is delayed.
It seems to me that there are two reasons for giving the reason for the delay. Firstly, it means that passengers can make a personal assessment as to whether they need to do anything to mitigate the delay. If I'm told that a passenger hasn't turned up and their baggage needs to be offloaded, then I know that there is a finite limit to the delay and I probably don't need to be making any arrangements. But if there's a technical problem which might not be easily resolved, then (if the doors are still open) I might want to phone and rearrange the appointments that I've got arranged at my destination. Or speak to the cabin crew about any connecting flight issues.
Secondly, of course, there is the question of compensation, since (whatever view you have of the rights and wrongs of the legislation) an entitlement to compensation in addition to a refund is dependent upon the reason for the delay. I have limited sympathy for an airline that deliberately chooses not to inform passengers of the reason for the delay to try to avoid paying additional compensation, since they are gaining an unfair competitive advantage over other operators.
Anyhow, back to reasons for delays. I can't offhand think of any particularly unusual ones that I've heard from an airline. It could only have been on a train in England, however, when the train came to a juddering halt and after a short period I heard the driver announce "I'm very sorry for the delay to your service. There is a swan on the line and we're waiting for the RSPCA to attend and move it."