Consider the description for history:
The history command can be used to retrieve commands you have previously typed in a shell.
However, fc and related variables FCEDIT and HISTSIZE exist in bash. There's no specific shell mentioned (which arguably might be implied to be bash), but fc is POSIX utility and hist is used on Korn shell variants (which is very close to bash); considering that we don't have that big of a following for other shells, they still are available, and it would make sense to include that as tag synonym for history.
As per terdon's comment on related question, which haven't gained much attention,
You are assuming that tags are rationally organized and inherit from each other. Unfortunately, neither of those is the case. But yes, we do want the pure history tag since bash-history isn't applicable t questions about zsh, sh, ksh, csh, fish etc., etc.
As I mentioned before, the portions involved with history mechanism occurs in other shells. Plus I think other shell users can figure out what works for bash and non-bash shell. So I'd say fc is a rational enough synonym.
fc. In fact, I don't really think there's any need for anfctag or a synonym tohistory. Is something actually usingfcas a tag? Creating synonyms "Just because" is usually not a reason to create a synonym...