Boxing vs athletics...

One of boxing's problems is that it is a star-driven sport; the wider public pays to see a particular fighter or fight, rather than watching "boxing" for its own sake. If you take Fighter A out of the equation, the event typically will fall through, and everyone suffers.

Athletics has had its own omerta issues over the years, but generally there is a clearer link between winning events and star power. Bolt aside, people pay to watch the events and the spectacle, rather than individuals competing. If a particular athlete gets popped, it's easier to fill that void with whoever wins something in their absence. When Ben Johnson went down and Carl Lewis started to suffer from injuries, Linford Christie (the next fastest) filled the star void despite never beating their times.

 

Most sports have year 'round random, in or out of competition, injured or not. And usually have to be tested at least 6 months before a possible return to competition.
Reason is that some athletes used their off time (even so called retirement) to juice themselves up to massive proportions, coming back and then go on a record breaking spree, like that French swimmer Bernard back in the day.

 

Athletics is worse.
Look at Usain Bolt.

 

The athlete nor his lawyer clearly hasn't heard of the Mexican Cow defence.