The source material that produces colophony is not the same as that which produces Abilar.
Rosin (colophony) is manufactured from liquid sap resin which is heated in its production process. Heating of resin can denature some components of the product, producing tars etc. that can have deleterious effects on the skin.
By contrast, the resin used to create Abilar is not produced from the liquid sap resin which exudes from a wound in the tree but from hardened sap which is collected several weeks or months after it has been exuded from the tree wound. This means that some of the volatile elements of the resin have evaporated and some of the other components of the tree are added to it.
Abilar production involves no heating of the resin whatsoever so there is no potential to create allergens which are quite commonly seen in colophony use.