Initially I wanted to make a separate cvar switch so anyone could manually turn taunts on or off from their client with a checkbox in the Audio menu, but the implementation of this is in the server code which means such a cvar would act as a server setting, not a client one so a switch cannot seem be implemented client-side. Taunts can be individually turned off by muting Voice in Audio settings instead, which works perfectly well and does what it should so I believe this should not be a problem for anyone who doesn't want to hear them for now.
Patch can be found HERE as file or HERE as text. This is my first C code patch for the game which took me quite a try to make so please correct any messy code I might have used. I tested this locally and it works just as it should in both DM and team games (haven't tested it in multiplayer between players but that should be ok as well). Hope the patch is good and can get in, I'm sure many would love taunts a lot as well

[EDIT] Updated the patch and added a cvar for it even if server side. The cvar works as a probability factor since playing a taunt each time someone frags is annoying. This switch both avoids annoyance with excessive taunts and offers a way to turn auto taunting off if someone wants to disable them on the server. Once again, this is better as a client setting if someone figures a way to make this client and not server based someday. For the current number of taunt voices per player, I set it 0.65 (65% probability of taunting per frag) but this should probably be increased a bit when there will be many taunt voices.
[EDIT2] Made the feature client-side which means auto taunting can now be individually enabled or disabled by anyone, including the probability factor. The code is still server-side but taunts are now sent and played only to those who have the cl_autotaunt cvar above 0 and no one else, so now this is exactly as it should be now. Re-download from the same links in this post.