For those who think some of us have some sort of hatred for OP...I think I can hold the opinion that the DL agent used proper discretion in not rebooking/allowing standby for OP, and at the same time understand and be perfectly okay with BE fares and customers. Those are not two mutually exclusive perspectives.

I also don't believe that it is hostile to tell OP that he should expect DL to abide by their own published rules/policies, regardless of how much any of us like/dislike them or how "fair" they are.

For OP, as a non-status, BE-fare passenger, the following discussions don't apply here:
- Flat tire rule, as OP's tardiness was due to something within his control
- SDS, as even if on on a main cabin fare, SDS to a later flight is not allowed unless GM+

The only variable at play is agent discretion. In this case, the agent used their discretion to stand by the rules. I would actually hope that any time "agent discretion" is in play, they make that selection the vast majority of the time, and allow exceptions to truly be exceptions that are rare enough and outside of the customer's control.

Perhaps for OP, oversleeping is truly an exception in his/her life. For that agent, though, OP may have been the 20th person who arrived late that morning saying they overslept/misread the departure time/went to the wrong counter/etc. The agent knows that if they make an exception for all 20 of those people, that's no longer making an exception, but rather setting an expectation that the published rules don't matter.