Threads of this exact sort have been made way too many times. I'll say this one final time so that you can become better educated on the topic.
The fist glitch is a problem in the Mojang code. MCSG is not the cause. MCSG cannot directly solve the problem. However, our awesome developmental staff have been figuring out ways to evade the glitch using new plugins. However, nothing seems to work just right. So we decided to remove the iron swords from the lobby to greatly reduce the amount of abusers of this glitch. Sadly, this does not solve the entire problem. There is another way to obtain the glitch.
In the fist snapshot revealing the features of 1.7, it was found that the fist glitch was resolved. Once the servers update to 1.7, there should hopefully not be any more fist glitching. Patience is key.
Edit: #BeatTheThreadLock