Some have criticized promoters and boxers for "cherry picking" their opponents to increase the chances of victory. Some dislike it. Most boxers will tell you they will fight anyone, anytime and anywhere. However, is it a good idea in the early stages of one's career (and towards the end of it if one has hit advanced years). Let's face it, some boxers are further in their development than others. The fight will not be well matched and could put you at a great disadvantage.
If I were a promoter I would have qualms about putting a boxer in with someone they are not ready for in the ring. It is not a lack of confidence, just practicality. There are many things you will not learn in the gym, that require the experience of the ring in a live setting. How you react to truly being hit, going the distance, the noise of the crowd.
Newly pro boxers usually look green in the ring for about their first 10 fights. They land fewer punches and make more mistakes than a pugilist with at least 20 fights under their belt. Boxers with more experience turn into sharks smelling blood in the water when a promoter sends in a rival for something they are not ready for. The rival boxer knows and it ends up looking like this:
(Photo credit and caption: ICanHasCheezburger site)
If you lose too early in your boxing career, it will cause problems with the type of fights you can get, how much you are paid in purse money and your sponsors, which helps to pay your bills as a boxer. It's better to pace it, choosing a natural and steady progression, rather than rush into a confidence battering defeat that could be avoided had you simply waited until your development was at a greater stage.