As with every sort of awkward, challenging conversation like this you gotta meet them where they are at.

They're your friends, find some area where you can agree about the subject. That doesn't mean concede points (never concede any points), but I am sure there is some point where you mutually agree "this is not okay." Then you just gotta branch out from there. Wear your opinions on your sleeves, but try to let them come to conclusions on your own. They won't call it settler colonialism day one. This might be something you argue on and off about for months, but people usually only come to realizations by themselves.

If you cannot find any area to agree on then they might be a fascist and you disengage.