I don't know where they get these people, but I had a SFO-LAX-YYC (LAX-YYC is UA-coded, AC-operated). Schedule change to SFO-LAX to make the LAX connection under the MCT.
First agent saw the illegal connection, and I proposed SFO-YYC nonstop. He said he could waive the change fee, but there would be a fare difference. I asked him why there would be a fare difference when UA if giving me an illegal connection, and he said my fare bucket wasn't available. I then asked what options he had to remediate this, and he offered a refund. Told him to leave it as is and hung up.
I wanted to file a DOT complaint to get that agent retrained (and then someone at UA would fix it for me without having to make another call), but I recently filed a DOT against UA on something else, so I let them have a second chance.
Second agent argued the connection was fine. I had to walk her thru how to read an MCT for that flight number pair. Once she was able to acknowledge the connection was invalid, she was happy to give me the SFO-YYC nonstop pending supervisor approval, which they approved.
Two calls totaling over 30 minutes for something that should be real simple.