There is also the inconvenient fact that the Mau Mau rebellion didn't break out till 1952, with increasing tension during 1951.
So grandpa Obama was highly talented. He managed to get arrested for involvement with a rebellion 2 or 3 years before it happened.
Which does not mean that Gramps or someone else in the family didn't tell this story or something similar. Sort of how by 1946 all Frenchmen were veterans of the Resistance.
Better still. Not only did he get arrested a few years before the Mau Mau rebellion even occured, he was probably the only non-Kikuyu in the the ranks of the Mau Mau. Once grandpa Obama knelt toward Mecca, the Mau Mau would have cut him up into little pieces. The Kikuyu were not fond of the Muslim slave raiders from the coast. I wonder if Kenya has any stolen valor laws in regards to the Mau Mau Rebellion. If so, Grandpa Obama would have a little legal trouble, if he is still alive.