These humans were being told that they were killing the people they were charged with making healthy and whole. On top of the whole 'How dare you suggest that I, a gentleman of means, am unclean!?' combined with 'Well this other gentleman of means and several of his peers say that you are wrong,' we have the very real and sadly common human reaction of '...but I'm the helper. I can't be hurting them because I'm the one who helps.'