I guarantee you that if the shooter had the power to do that then he would have, but the point of the hyperbole is that violence does not solve all problems and instead can be quite detrimental.
The ideal world would have people vote for politicians which oppose privatized healthcare and would make his profession illegal. An ideal world would see class action lawsuits bankrupt him. An ideal world would consider his company denying ability to get necessary care, despite qualifying for reimbursement, as an illegal act similar to assault, and have him sent before a jury.
The outcome we got is the worst possible outcome: the USA elected a bunch of explicitly pro-privatization officials and somebody felt violence was the only resort.