If, as you say, Onoki has it genetically, then he would be related to Muu, wouldn't he? As you quoted "a technique limited to inheritance by blood", Onoki by that logic, must be blood descendant of Muu. As for your point of why can't ... use ....? Think about it this way, each Shinobi who is born with a certain set of affinites is automatically linked to a Kekkei Genkai, the Kekkei Genkai is something created when a person with two affinities combines those natures. It takes certain matchups to get certain Kekkei Genkai.
LOLOLOLOL I HAD A GOOD LAUGH READING THIS. Quite a pathetic retort. Do you even understand my point about Mei? And Onoki?
You say: "It takes certain matchups to get certain Kekkei Genkai"
If they can use KKG because they have multiple natures and "certain matchups" (as you claim):
i) Why is Mei
ONLY LIMITED TO Boil and Lava release, when potentially she could also use Wood release, since water + earth is a "matchup" that she has? Can you explain this?
ii) Why is Onoki
ONLY LIMITED TO the KKT when he potentially could use Lava and Scorch release as well, if earth + fire and fire + wind are "matchups" he possesses?
iii) Danzo implanted the Wood release KKG gene. Why is he
ONLY LIMITED TO using Wood release, and not its constituents ("matchups"), water and earth release??? This example alone shows that your so-called "matchups" are
SEPARATE from the KKG itself. That is, to have the KKG you WILL have the requisite "matchups", but having the "matchups" is not enough to have a KKG. This is also the reason why KKGs cannot be copied regardless of your nature. (If your logic is right, then an Uchiha with fire and earth natures should be able to copy Lava release from Mei, but it is
known in the Narutoverse that KKGs
cannot be copied, period.)
Dude, seriously. Make some sense please.
I expected more from you, really (and this is a compliment).