Why Some Dentists Are Afraid of Taking my Bonding Off?

I would remove the bonding and place porcelain veneers.  In one week you would have a gorgeous smile that would resist staining and make your teeth the perfect shape, size and color.  Having the bonding removed so you can have braces to find out the teeth themselves are less than perfect is an exercise in futility.

The term "bonding" can refer to several different types of restorations.  If the type you're referring to is tooth colored plastic resin between the teeth it should be a simple matter for any dentist -- the one who placed it or your orthodontist -- to remove it.  If on the other hand you are referring to a restoration that covers the entire front surface of the tooth, it might be better for the dentist who placed it to alter it since that person would know exactly what was done, how thick the material is, etc.  I gather that this bonding is just between the teeth and was done to close residual IPR spaces, so it should not be difficult for your orthodontist to remove it.  Ask him/her why she wants the dentist to perform this procedure; perhaps there is a good reason.