First its not only kikuyus who were targeted - Gusii, Luos and Luhyas also suffered greatly.
Kalenjin did not sell the land to immigrants - in any significant numbers - those who settled bought the farms from white highlands.
This was mostly in Nakuru, Uasin Gishu and Tranzoia.
There were many complains and warning of war if settlement went on.
Murgor father was 1st to declare war against immigrants in 1963.
All through 1960s - Kalenjin complained - that settlement was going on without any fairness - that kikuyu were being given preference to buy land.
Remember few really bought the land - it was LOAN from British gov.
So nobody really bought the land - maybe just the deposit - to unlock the loan.
Kenyatta then put Moi as VP to placate Kalenjin so settlement continued
Moi knew Kenyatta had placed him there to stop kalenjin murmurs and war cries.
All was good until kikuyu leaders in 1990s wanted to remove Moi.
Moi remembered the land issues and re-opened it - Majimbo - both in RV an Coast.
He knew he would not only expel voters but hold hostage opposition leaders.
And it worked.
Of course it resulted into many deaths.
Before 1990s - kikuyus and others had been living in rift valley for 30yrs - people had even forgotten about land grievances.
Folks had intermarried - lived together - nobody even quite recall the land issues.
Until Moi started opening the old wounds and telling people to expel immigrants.
And of course he started burning few house of kalenjin - knowing it would spark war.
Which kikuyu had been attacked in 60s,70s, 80s? NONE.
Until Moi started the land clashes as he was pinned on the wall by larger tribes.
Of course Kalenjin were more than happy to board and attempt fix historical injustices.
did kikuyus just take the land or buy it from your people? Now that you have buyers remorse you take it out on your hapless neighbors. most of those displaced actually were just poor people living in informal settlements working in rv and possibly working for Kalenjins. Kikuyus won't go after the most weak. even when mau mau attacked in Lari it killed those that were abusing their privilege. Kahangara was for years maiming mau mau suspects and would even drag suspects with his car or horse. he had to be eliminated. Mau Mau was fighting the British and its loyalists.
for kalenjins they were victimized and killing kikuyus because kikuyus were voting for opposition
you can't compare mau mau war and ethnic clashes.