The DNA presence only confirms that there was interbreeding happening, not what kind of conditions they were happening under. Knowing what I know about our species, especially from the early days, IMO its equally likely that we intermingled via war/conquest (in the form it would have existed for hunter/gatherer societies) and incorporated via slavery. My guess is that history contains examples of both (peaceful and violent exchanges) for each of Neanderthal, homo erectus, and Denisovians, plus maybe others that history isn't as aware of, depending on how diverse hominids got before homo sapiens got settled in everywhere.
Our species is capable of the full spectrum from good to evil and even today we have a large amount of psychopaths in leadership positions.
Though we are the first species to be aware that other species have gone extinct and wonder how much of that was directly because of us. And it's not like any homo sapiens that exist today have any responsibility for what happened to species that went extinct before recorded history began anywhere on this planet.