its really very simple:

pacquiao wants to fight under the commission's rules.
floyd wants to make his own rules for manny and himself to follow.

there is no reason for manny to have to follow those rules.

where's the controversy?

in an attempt to bully manny into agreeing to fight under his made up rules, floyd slandered manny.

manny, having been slandered, decides to sue floyd.

again where's the controversy?

its all very simple...floyd wanted to dictate the terms of the fight which were outside of the sanction bodies rules... then he decided to break the law and slander him in an attempt to shame him into fighting under his made up rules... now manny wants him to justify his slander or face the consequences. (these consequences are law. not made up rules. but law.)

there is no controversy here.