The strongest interpretation of the idea expressed by Gell-Mann Amnesia is "You set your posteriors to be different from your priors based on journalism more than you should be and you do not alter this difference upon seeing evidence that should indicate imperfection in journalism". i.e. it warns you that you are likely over-weighting journalism.

Fortunately, most journalism is useless for information transmission and likely rarely alters behaviour - the latter having been chosen first with the journalism being used as justification. To that degree, the fact that most journalists are usually low quality information sources is not particularly dangerous since you never use them to do anything different from what you'd do.