Well, what's so bad with "time travel" after all?
That it leads to paradoxes like "two people kill each other, each one being killed by the other before he pulls the trigger" in the case of a tachyon duel. And that kind of paradoxes (unlike the "I killed my grandfather" paradox) can't even be explained by alternative histories/Everett branches.
Link: nextbigfuture.com/2011/11/faster-than-light-neutrinos-opera.html
Link: science20.com/quantum_diaries_survivor/opera_confirms_neutrinos_travel_faster_light-84763
Paper: kruel.co/paper-neutrino-velocity-JHEP.pdf
Previously on LW: lesswrong.com/lw/7rc/particles_break_lightspeed_limit/