The reports cited by you, myself and others refer to--and this is a contemporary conclusion--such machine-gun fire as a celebratory burst over the sinking of these two ships inside 20 minutes, itself not a common event and one which surprised even the Japanese since they expected that torpedoes would have been required to sink these vessels. IIRC, the Japanese had actually placed a torpedo strike in the air but were fortunate--at least for them--to have been able to land those birds, with the torpedoes no less, once they received word that the two cruisers were already on the bottom of the Indian Ocean. In addition, as I pointed out, machine gun fire from Dorsetshire which Agar reports as from the searchlight platform still issued from the ship and in return to a--read that as 'a', as in singular--Japanese plane which fired a 'triumphant burst'. Even then Agar allowed that matters could be characterized as other than willful.
These facts do not lend themselves to Raven's assertion--again, one he has not documented--that the Japanese engaged in a systematic and repeated machine-gunning of the survivors in the water. Let's recall that this gunfire was admitted by RN survivors to have occurred while the vessels remained above the water's surface and were even then returning machine gun fire themselves against the aircraft.
Asserting that survivors who were in the line of fire 'would have sympathy with Raven's idea' is not the same as writing that the Japanese actually--and willfully--targeted survivors in the water for 'repeated machine-gun fire'. And given the evidence which has been supplied thus far, it would be wrong to do so. This is an object lesson in gathering a sufficient amount of documentation to arrive at a reasonable conclusion. Raven reflexively condemned the Japanese--without citation, I will again add. He has repeatedly done that on this Board over the years and on various subjects so, yes, I have ample grounds for interpreting his words in the context by which they are almost always written, in this instance: "...the repeated machine-gunning of the survivors in the water...."
Raven very much meant what he wrote; the trouble is the facts don't bear his comment out.