You can be casual and a jerk. You can be friendly and professional. Someone telling me "oof" when my business is offline and losing money (or insert major issue you've caused me) isn't a social nicety, it's something I would expect a buddy to say if I told him I lost money playing poker.
Please don't make light of their issues. People want to be treated seriously when they're having a problem.
You can't tell people they're entitled for disliking how you're treating them in a serious situation, and call it empathy in the next breath.
It is a front line support rep, it is the same as some guy at McDonald's. Yes, I think people are entitled when they feel they have a right to be mean or difficult to some person who is just trying to do their job and is making a plausible attempt to be nice to you. You can't read that workers mind, they said one word that can be plausibly used in either circumstance. That word expresses anguish that their customer is having trouble. That is empathy if it was used sincerely. It is not the south park episode with the cable company workers.
There’s nothing wrong with expressing anguish. And I happily fire customers who have a problem with that. Life is too short to deal with that level of entitlement.
If my customer is having a problem, I can try being friendly after the communication is already ongoing, problem has been aknowledged, and it is on his way to be fixed. Ending in a friendly tone is a big plus. Starting with it, not at all.
On the other hand, as a customer, having to deal with you at all is already stressful enough, i'm paying you and still losing time over your screw-ups, and still you start with an "ooof". It would give me a feeling of "not only i'm losing time, i'm also being joked on".
Being professional and gradually friendly is simply the most secure way to operate, because every person that contacts you for a problem, big or small, doesn't want to contact you to begin with. Don't "ooof" me please.
The person could have just copy pasted the canned response with no help and it sounds like a lot of people would have been happier with that. At a minimum, they wouldn't be hating on the customer support rep personally.
They are just people trying to do their job and I don't recall a single support rep that wasn't just trying to do their job well. People are complicated and socializing is hard, especially when it's not in person. What we do is almost always not life and death. We shuffle bits around between computers, we shouldn't take ourselves so seriously. There is no reason people can't be nice to each other in these interactions.
I repeat, there's a big, big value in being friendly and basically "a human", but the very first starting interaction must be serious, not a joke.
People realize the guy there is not the whole company, but they also realize they are the only way to get communication going, and losing time only to be greeted with an "ooof" can be annoying.
Of course it also depends on the specific case (how big the problem, how angry the customer, how long the "ooof"), but I've been on both sides for a couple of years now and starting in an over-frienly manner sets the mood for an "un-important" context.
And, in particularly bad cases, that could sour the entire conversation.
It's more than likely some dude that is just starting their career that has almost no training that is trying to the best of their ability to express empathy, provide a workaround, and make the customer happy. He doesn't control what gets fixed. Why do business interactions need to be devoid of social niceties? It's some software company, not a morgue.