Boxing is one of the only sports where the best can actively duck other top athletes No one ducks anyone in the tennis circuit. Imagine if instead of getting titled stripped by not defending belts against 'too risky' opposition boxers got their license stripped (worldwide, they couldn't fight anyway), how good would that be for making fights happen which should be happening ! The only way boxers could duck other boxers is stay on the sidelines and not earn any money
Taking a boxer's license is taking away his livelihood. You're taking away his means to provide for himself and his family. That's going too far. It's like Guido said in Risky Business. "Don't **** with another man's livelihood."