I agree with Oroka’s assessment of Ramsay in his own kitchen(s) and I do think that carried over into his behavior on many of his shows, but I think he has mellowed over the years and I agree with you that in “Kitchen Nightmares” he seems to be able to keep his temper down (mostly) when talking to the staff who are just trying to make a living working around the particularities of their bosses. In fact, in this particular episode I think he did a spectacular job of reining in his fury to point it like a laser beam solely at the couple.
There’s something about actually working in a kitchen with a staff that brings out the worst in him: if he can keep himself as an outsider looking in, he has much better self control.