Only one fighter can possibly be ducking the fight

If you want to avoid fighting someone whilst saving face then you make an impossible demand over a particular issue and claim the other side wasn't willing to compromise. If you have no intention of pursuing the fight from day one, then you make sure that whichever issue the talks break down over is one which you can use to smear your opponent and make it seem like it was his fault for the fight failing to take place. If Pacquiao genuinely wanted to avoid fighting Mayweather then the one issue, without question, that he would avoid making an impossible demand over is the issue of drug testing. He could have made excessive demands over money, over the weight or over any number of things, but doing it over drug testing results in him coming away with a cloud of suspicion hanging over him. If Pacquiao's camp were the architects of this then it's the stupidest attempt to duck a fight that I've ever seen (one where Pacquiao comes away from it looking like a drug cheat). In contrast, if Mayweather wanted to avoid the fight he would have made sure that it was the issue of drug testing that the talks fell apart over. He would accept a 50-50 split in money (who cares what percentage you get from a fight that you have no intention of being a part of?) and he would accept the weight demanded by Pacquiao's camp because those are issues which would both bring Mayweather criticism (too greedy for demanding more than a 50-50 split, or too scared to face Pacquiao at his own weight). He would instead have made an impossible demand over drug testing and then, when the talks broke down, he would have indirectly implied that Pacquiao pulled out of the fight because he's a cheat. The idea that Pacquiao ducked the fight isn't credible. Either Mayweather ducked the fight or Pacquiao really is on steroids and didn't want to get caught. It would be complete idiocy for Pacquiao to get out of the fight using the issue of drug testing.