Many of the newly uninsured are presumed to be those that now buy insurance because of the ACA penalty.  The CBO presumes that eliminating the penalty will cause people to ditch their insurance.  This is an assumption and it is not clear that it is correct.  After all, the penalty is far less than the cost of insurance.  As far as the health care industry is concerned, they will oppose anything that lowers their income so in a sense their opposition is a very good sign.