Citation, Documentation of Sources

Q. The way sports writers and fans write the hortatory phrase “Go Giants!” (my home team, and no reflection on them) drives me nuts. Shouldn’t it be “Go, Giants”? It’s direct address, after all, and there is a vast difference between the two commands “Kill Bill!” and “Kill, Bill!” The athletic directors whose columns I’ve edited just scoff that it’s accepted “sports English” to write “Go Bears/Giants/Frogs!” but I just “go bananas.”

A. Ah, sports English. Yes, that’s what it is, and there’s probably no fighting it, although as an editor you are justified in inserting the comma.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]