surface rust usually indicates to me where paint has been worn off by abrasion or sun/wind and rust has skimmed the bare metal surface. that appears to be bubbling, indicating rot from inside. You need him to take a picture with the door bottoms in the sun and not shadow to be sure, could be the shadow just making it look bad.
although my doors didnt have as much rust showing as those doors and I wouldnt describe them as anything but rusty. see the door bottoms at the bottom of the pile.
