I had the same crash using that cheat too. Deleting the simulation file in the autosave folder fixed it for me—game loaded fine after that without needing to delete the mod.
It had them. Introduced in Alpha 9, but subsequently removed.
Ironically, adding hard counters to 0 A.D. will make it more like Age of Empires...which is something you seem to argue against
Forcing a bad translations there (On Transifex) isn't gonna help though, you need to update the in game string, then when translations will be pulled and uploaded to transifex, people will translate it better.
I will try Transifex then for a quick fix. Ideally I think the message should be different depending on whether you are a spec or player.
If spec -> "Joining as spectator"
If player -> "Rejoining"