When the tag is muted and topic contains that tag, we should not mark that message as NEW.
There are 3 possible settings which site admin can set.
remove_muted_tags_from_latest - always
It means that if the topic got at least one muted tag, we should not mark that topic as NEW
remove_muted_tags_from_latest - only muted
Similar to above, however, if at least one tag is not muted, the topic is marked as NEW
remove_muted_tags_from_latest - never
Basically, mute tag setting is ignored and all topics are set as NEW