Yes because FAA understands well the maintenance and training standards of US airlines. These are factors that depend on airline, not airframe, and affect the likelihood of crashes.
I can not speak to Lion Air, but Ethiopian Airlines has a good maintenance and training record. It is widely considered the best airline in Africa and does maintenance for a lot of other airlines on the continent.
All airlines that fly into the US - including Ethiopian - follow FAA rules on maintenance and training. So the FAA already understands the Ethiopian standards well, since they set them.