there's very little difference between diesel and kero except that kero is alot more filtered, and has no additives, colorants and dyes. although Kero has very little lubrication additive (actually none) it is used as an anti gel additive for diesel in the cold (below freezing) months. any other stuff you would use may leave a bad (for a diesel engine) residue or vapor.
i would suspect the reason for using kero is that since it starts out clear, you would see the difference when the filter housing is actually clean. a couple of swishes and a light wiping should return a clean bowl and housing, with proof in the clean appearance.
using diesel would only add more colored dyes to dirty up the whole thing.
atf is OIL, it has sticking, gelling properties. those dont help remove the grime and sludge.
on an off topic, using kero as fuel in the winter does yield less 'power' since kero has less btu energy in it per gallon. but this must be done to keep diesels running continuous when its freezing.