> "Great Replacement Theory" is an inherently racist ideology
No, it is neither racist (edit: as described by Kirk) nor an ideology.
It's an accusation about the intentions of others, in a "the purpose of a system is what it does" kind of way (faulty logic — as I've argued on HN before — but not bigoted), based on observing demographic trends, the rate of immigration etc.
It is deeply conspiratorial thinking, but it does not claim that the people being "replaced" are inherently superior. Thus it is not racist even if we establish that the ingroup-outgroup distinction is racial, which already requires a quite broad conception of "race". (And Americans really are strange about that, in my opinion. There have been multiple occasions where I have been told that Americans generally consider a specific person to be "black" and I have deeply struggled to understand how that could be.)
It is perfectly legitimate to suppose that the existing population of a country has a greater right to continue to exist on that land, and for their offspring to live there, than those who are petitioning from abroad to live there. In fact, it's hard to argue that a legitimate nation exists, in a place that lacks a government trusted to determine questions of citizenship. Besides which, one individual's use of a term does not necessarily carry every other user's intent.
In brief, Kirk never argued that someone should be extradited, or lose citizenship, on the basis of race. Nor does that argument follow from anything he said.
And note that you have not at all addressed the point about "words that support killing people".
> In general, I haven't seen people making the hard assertion online that his words justified his death
I have been shown many people outright celebrating. This is not something that can be feasibly done by someone who has normal psychological aversion to death and doesn't consider the death justified.
> But I have seen plenty of "I don't think Charlie Kirk should have died, but the philosophy Charlie Kirk espoused shouldn't care if Charlie Kirk died"
I've seen plenty of messages that included the second part without the first part. But regardless, this reflects a plain misunderstanding of that philosophy.
Again, no pro-killing ideology here, outside of e.g. support for potentially-lethal police force to apprehend criminals in the act.