I understand why that might bother you, but it's a fighter. Gameplay > realism/lore. Same reason why D'vorrah's/Alien's blood doesn't damage opponents. You can find plenty of unrealistic things for any character. The gun characters don't reload, they take lethal brutalities with no apparent harm done, blocking weapon attacks and bullets somehow negates most damage, we can go on... point being they add to the gameplay experience, which is paramount to arcade fighters.
Funny how back in the 90's nobody complained about this. Only now that graphics are getting quasi-realistic, do players feel that realism is needed.
I'm firmly of the opinion that if you can do something funny or awesome (throwing chainsaws any number of times), the opportunity should never be missed because it couldn't happen in real life. The point of video games is to do disgusting, goofy, impossible shit that we can never do. I don't plan on beating any poor fucker's brains in with a meat tenderizer, or throwing a chainsaw at him, but I will do it in MKX with a smile on my face and a boner in my pants.
Mostly it's a matter of how goofy, how impossible do you want it to get. If Leatherface grew fairy wings and flew around the stage, that would be pushing it. Things at least grounded in reality seem reasonable to me.
I can at least conceive of throwing a chainsaw, and I can ignore that he pulls it out again.
