Just to clarify: you're saying that genetic analysis appears to rule out current natives being (at least partially) descended from a pre-clovis population?
Correct. The evidence isn't exactly overflowing but what little there is indicates the Clovis migration was not a peaceful one and existing populations either met a violent end or were forced to move to areas where their populations couldn't be sustained and slowly died out.
The parallels to the European genocide of Native Americans has significant consequences to two groups of people. The first is the white supremacists/edgelords who think an invasion from thousands of years ago means the actions of colonial Europeans as well as ongoing social justice issues with native Americans/reservations are somehow justified or deserved. The second is the far larger but far less dangerous group of people who think native Americans are somehow inherently morally superior and/or that European colonialism is responsible for all the world's problems. To them it's an article of faith that aboriginal peoples do not and cannot commit large-scale atrocities.
These two groups can make discussing and teaching American pre-history very difficult.
I don’t understand how it would be possible for the Clovis culture to conquer an earlier people without leaving a genetic record. I mean we even have Neanderthal DNA in each of us. Surely they would have intermingled?
One answer would be that there was no conquering. That could happen via a few possibilities:
1. pre-Clovis people were so thinly spread that Clovis was able to just fill in the gaps
2. pre-Clovis people had actually essentially become extinct before Clovis arrived. It's not easy to see how that would be the case in a continent(s) of this size, but not actually implausible.
3. as a combination of the two, pre-Clovis culture was completely nomadic, and their constant migration kept them out of the way of Clovis until a point where their population was so diminished as to leave no descendants, even via inter-breeding.