this does seem to be a pretty huge conflict between tag muffling as a safety/self-moderation feature and repost tag removal as inherited from tumblr
if both of these are gonna stay the same, there really ought to be hidden tags: they don't show on the post or enter it into the tag pages, but they're there for the safety features, and are inherited from the original.
allowing folks to put them on a post in the first place would also allow them to tag something for muffling without entering it into the tag page (so you don't have your post catalogued in a page of phobias or potentially triggering things, for instance)
