Ok, I will try one last time, because this is pretty boring -
It is actually not illegal, depending on how you interpret the rules, to bring an axe into the octagon and hit you opponent with it. There is no specific rule that says you can't do it. Does that mean it is a legal technique? No, right? that would be a really stupid argument to make, right? If you agree with that, then you know what your argument is.
And to round it off - Trying to eyepoke is technically illegal, depending how you read the rules, even back then -
- Unsportsmanlike conduct that causes injury to an opponent is illegal
www.ufc.com
So yeah, they did not so much have to change the rules, as they had to specify specific things because people like you who read the rules and interpret them without honor or sportsmanship.
The problem is grey areas, and scrupulous people who are willing to abuse the grey areas, and when called on it they will say "but but it is not technically illegal".