So, Langevin's views were "largely accepted" at the time. By whom? Do we have evidence of wide acceptance by Indigenous people at that time? That would make the case for honouring his name more convincing. 

More convincing but not absolutely convincing. Even if there was "widespread acceptance" in Indigenous communities, there were always champions within them who opposed such views and the practices that flowed from them. Those champions, as all but of a few of us now acknowledge, were on the right side of history. So do we continue to honour those who opposed these champions or chose to ignore them?

Very good article all the same, and the idea of some sort of objective "test" can go a long way to helping us sort out our ideas together.