You're wrong. Like Ruto said in some interview during Waki commision. Land is not the problem. It as much as problem as it in Coast or like Nyanza feeling of marginalization. It more a general feeling. It can only be sparked if there is general widespread feeling...like 92/98/07...certainly of political nature.
When you talk about the areas and flashpoint - I don't know which one - the current one in olmelil is case where Kipsigis and gusii are strangers - the land there belong to maasai and is in narok county - what I am sure sparked this - is nothing more than cattle rustling gone wrong. This is true with flashes in Nandi/Luo border of Chemelil/Muhoroni/Kisumu. The same is true in clashes within kalenjin in transzoia, elgeyo market,baringo, turkana, samburu and recently in narok north btw kipsigis-maasai- name it. This is more localized daily occurrence that flares up.
The immediate problem is cattle rustling. Land grievance need huge political nexus to explode. Cattle rustling doesn't. One guy wakes up, steal cows from another tribe or sub-tribe, kill or is killed..and there it exploded.
Small sparks(cattle rustling). Huge sparks (Land clashes) need to start that fire.
It's been a hundred years but I don't think there is any doubt which tribe "belongs where" in Kenya. If anything, it was less certain in the 70s and 80s than it is today.
The OP wants to know why Kalenjins seem to be involved in ethnic clashes with different tribes. It has nothing to do with the Kalenjin per se. But rather that their tribal lands appear to have been "occupied" - you need not look further than where the flash points happen.
The Marakwet/Pokot issue is different and could be more amenable to the suggested solution of education and end of cattle rustling - change of cultural behavior. That might have something inherently Marakwet/Pokot in nature.
The other one has more to do with the common feeling among Kalenjins that some people are "foreigners". Politics can trigger it. But sometimes it just explodes "without warning" or even after a domestic dispute. It is not an inherently Kalenjin attitude - you can sense it sometimes among the pwani peoples. It's more of a national problem.