The phrase "to kill the messenger" means getting angry and punishing the person who brings bad news or delivers an unpleasant message, even though they are not responsible for the problem. Full definition
It's like killing the messenger, because, in autoimmune thyroid disease, the problem is not with the thyroid gland. (thyroidpharmacist.com)
It is a well established principle in politics that if you can not kill the message, killing the messenger scares others away from attempting to carry it forward. (judithcurry.com)