Besides the risk of spreading ill-will, it also seems to me that price discrimination can be risky because there is no way to firewall it against a correlation with some legally protected class.
Edit: Also something that occurred to me just now - price discrimination seems to me to lead to a reductio ad absurdam - suppose that it was absolutely perfect and captured all the consumer surplus; then doesn't that destroy the rationale for the transaction in the first place and make it purely exploitative? If it is not desirable to get to that place, then maybe splitting the surplus at least evenly between producer and consumer is the way free markets should work?