Yeah, the “I’m sorry you feel this way” response really irked me too. There are so many different ways to respond that would have been more appropriate and conveyed the same message.
The “I’m sorry you feel this way” is the first thing you learn from that HR workshop about communication when you get a promotion where you have to manage people.
The thing is that having a lot of people working in corporate environments, where you constantly need to be political and backstab others to achieve some task you've been given, this is the norm, so for many this is normal, the type of stuff where they say: I'm just trying to be helpful and constructive, but for anyone not having time for this corporate double-speak, this seems rude and condescending.
I understand this is corporate double-speak, trying to signal empathy without admitting any fault. But it’s the fact that it is double speak that is so irking. It might be appropriate in manger/subordinate/HR conversations - but in this context it just adds insult to injury (IMO).