The issue seems to me the attitude, not the content, of the call. It is hard to know the full picture from the OPs post but compensation probably did not need to be brought up and an apology for the delay was in order. This apology should have been followed by a suggestion to book longer connections....
Ice...I am very glad DL, AA, and all my airlines allow me to decide how short a connection I want to accept (within the rules). I would hate it if DL no longer allowed 40 min connections at ATL or AA 40 min connections at MIA. If I misconnect, I would not blame the airline. However, I would also expect the airline not to say it was my fault; I should not have booked it. I took a risk that they would be on time, they were not on time, so now they need to do their best to accommodate me, not blame me for the result of their lack of on-time performance.