I don't think they're divisive as such, I'm not friends with anyone who would have problems with acknowledging that the land we are on was once XYZ tribe land.
But everyone is annoyed with the rote recital of stuff like this:
"City of Adelaide acknowledges that we are meeting on the traditional Country of the Kaurna people of the Adelaide Plains and pays respect to Elders past and present. We recognise and respect their cultural heritage, beliefs and relationship with the land."
We don't start every meeting with "God Bless the King".
We don't start every interaction with a reminder "I'd like to acknowledge that this office and the building within which it resides remains the property of Peregrine Corporation."
It's become rote noise.
At the start of a large public event, where an MC is introducing speakers or the AFL grand final is about to kick off, it makes a lot more sense.