There are many facets to this. But let me mention one. The problem of tribalism is aggravated by the assumption that if one opposes a particular candidate, it is because of his/her tribe. Therefore, anti-RAO are presumed to be anti-Luo while anti-UK are presumed to be anti-Kikuyu. That explains why criticism of RAO is presumed to be tribalism in some quarters. Ditto criticism of UK as anti-Kikuyu. Way forward? Understanding that not everyone who criticizes a leader does so because of the leader's ethnicity.
All my friends are heathens, take it slow. Wait for them to ask you who you know. Please don't make any sudden moves.