I'm sure he'll share his explanation of why he chooses to do it this way but in general with females that have just laid, any hit of the sent of their eggs supposedly can cause them stress and an urge to find their clutch and continue to incubate them instinctually. So they stay in new mother mode instead of moving on to feeding. I have not experienced this though, washing with water has been enough for my girls to forget about the eggs and resume feeding.