Is the implication that someone affiliated with Twitter took down GitHub because of something someone hosted there? Does that honestly seem plausible to you?
I'm not saying "that happened", I'm asking about the possibility. Does it seem plausible that someone sympathetic to Twitter launched an attack on GitHub in retaliation? Absolutely.
Honestly, while it's certainly possible it doesn't seem plausible to me. I have a hard time seeing someone with the extreme emotional connection needed to lash out because of the leak also having the technical sophistication required to bring GitHub down.