It wasn't his breakfast, it was his dinner and it was apparently eaten by two privates of the Sappers & Miners. It any case the President's residence was a public not a private building and, under the Laws of War as they were observed at the time (see Vattel on this), its destruction was legitimate.

As far as I know, the British only burned one private building in Washington and that was a house from which a sniper fired at Ross. Ross maintained very strict discipline among his troops, only 700 were permitted to enter the American capital and their officers kept a careful eye on them. There was considerable looting after the American government and forces fled the capital but all American eyewitnesses who testified before the congressional committee struck to investigate the matter are unanimous that it was carried out by the "lower orders" of the city. They are also unanimous in stating that British discipline was good and the troops were well behaved.

I suppose they wanted to be invited back again.

Compare/contrast with the French army in the Iberian Peninsula.

dg