Yes. It was really bad what these people did. Anyone who has not read these two book should read them

1) Britain's Gulag: The Brutal End of Empire in Kenya
2) Histories of the Hanged: Britain's Dirty War in Kenya and the End of Empire

You will really be mad to know what happened to our Grandfathers and Grandmothers and the role the home guards played

One of the most significant questions on the recruitment of Africans
into the colonial Kenya police, and at the same time one of the most difficult to
answer, is whether the British recruitment process was influenced by a
tribal bias. Although some groups were proportionally overrepresented
and others underrepresented, there is little solid data as to why. Without
doubt, the British were very conscious of differences, real or imagined,
among the peoples of Kenya Colony and Protectorate. J. H. Patterson
was not atypical when in the early days of British East Africa he commented that, "The Wa Kikuyu have a reputation of being treacherous people" and the Kavarondo (Luo, and Luhya) were "industrious, simple people ... on the whole about the best of the African
tribes. In the Kenya police there were few Kikuyu and many Luo,
Luhya, and Kamba; the latter three groups in fact were said to be the
"backbone of the force." In the 1920s Commissioner Roy G. B. Spicer
noted that the Kamba responded to any call for recruits in "a huge number," and that the force was becoming "overburdened" with "Kavarondo."
The question of literacy also became an important consideration in the
recruitment of African constables. While African police were paid bonuses if they were literate in English, Kiswahili, or one of several other
indigeous languages, there was by 1926 a suspicion of the literate recruit. A decade later the annual report stated that there was
a concerted effort being made to recruit "suitable Africans from, the more
backward tribes of the Colony." A 1942 report revealed that the evidence indicated that the illiterate made a better policeman than did the
literate African, and that "the policy of recruiting literates should be pursued with great caution." By 1949 the annual report showed that illiterate recruits and "the best material" were mostly from the martial Kipsigis
and Nandi and the reliable Kamba; literates were primarily Luo, Kikuyu,
and Kamba. The police commissioner went on to state that the uneducated had greater qualities of reliability, manliness, sense of responsibility,
and discipline, while educated young Africans were, unwilling to start at
the bottom and expected preferential treatment within the force. By 1953, the composition of the colonial police force was: Kamba 18%, Luo 11%, Luhya 10%, Nandi 10%, Kipsigis 8%, Kikuyu 2%, Masai 1%

Why have you left out the fact that the native colonial police officers that terrorized your grandparents were drawn from the loyal akamba, luo, luhya, and kipsigis and nandi communities because kikuyus were thought to be treacherous and couldn't be trusted and thus were very few in the police force? Read this article:

https://www.jstor.org/st...#page_scan_tab_contents

I find Anderson's Histories of the Hanged as perhaps the most dispassionate, truthful & fair account.

Anderson tells us that there were 3 groups opposed to the war among the Agikuyu, Aembu & Ameru:
1. Christians-Devout Christians were opposed to oathing as it contradicted Christian teachings. The Catholic church recognised some who were killed by Mau Mau in Nyeri as martyrs.
2.People already in power-Chiefs, administrators.
3.Traditionalists-Devout traditionalists considered this oathing led by young men as a subversion normal oathing.
I was reading juzi how even the Njuri Ncheke had condemned Mau Mau!

This thing wasn't as easy to dichotomise as we do today. Most were perhaps opposed to the fighting but were for greater independence.

He was killed by the post independence Jomo Kenyatta govt. It is said he had gone back to the forest(to fight)

Other accounts point to rivalry between him and Meru king Angaine