The US government puts them on the list. I don't care that they are on the list, but it does mean they can't sell the devices in the United States. If that ever happened to Motorola, and there were still no other devices that Graphene OS supports, then there would be no options left.

> placed on the do not trust list?? who places them on this list?

The President of the United States, or members of the Federal Government that have the various levers of power.

> and why do you listen to the people who place them there

If they won't allow the devices to be imported then it's not really an option. Which also means they wouldn't be allowed to connect to the cell network.

Or they could be barred from all Federal or State facilities, having to be left in a faraday bag upon entry.

Federal grants and loans to states and companies could be denied if company policy allows the use of those devices for corporate communications and purchasing decisions, etc.