Again, this is fully TSN's fault. You can spin it all you want, and yes I know twitter isn't a get out of jail free card for spewing garbage, but this SPECIFIC incident was caused because TSN aired that on live TV during their own broadcast. TSN is liable, and the tweeter will escape any damage other then an apology.
Again, it is not fully their fault. If he doesn't post it, it doesn't get on TSN's feed. That's not spin. There are consequences for libel - what the tweeter did. Even if they hadn't broadcasted it, who knows if it doesn't become viral, and then news, and then he alone gets sued. It all comes back to him. He had the audacity to lie.